Lead Coulombmeter, II.-Franz Fischer, Karl Thiele, and Edward B. Maxted.-The authors describe a method platinum without previous oxidation, and a titrimetric of drying and weighing electrolytically precipitated lead on method of determining lead in presence of an oxidising or reducing acid. With boron fluoric acid, silicon fluoric acid, and p-phenolsulphuric acid as electrolyte, the connection between the amount of lead separated, the amount of free acid present, the concentration, and the temperature was determined. The addition of o'r to I grm. per litre of colloidal substance to the electrolytes does not affect the accuracy of the lead coulombmeter, but I grm. per litre of colloid completely prevents the precipitation of lead. The best coulombmeter is obtained by using lead boron fluoride. It may be used with currents from 0.14 to 14 ampère per sq. d.c.m. process" to a thorough investigation, in the course of which | iodometrically. By a combination of the two methods the they determined the solubility of the hydrates of thorium percentage composition of a mixture of ferro- and ferrisulphate in sulphuric, hydrochloric, and nitric acids, and cyanide can be determined. have found that the presence of phosphoric acid hinders the separation of sulphate, and when large quantities are present no sulphate precipitate is formed. When the hydroxide which is to be converted into sulphate is dissolved, only hydrochloric acid is used technically, and from the results of the solubility experiments the authors conclude that the use of nitric acid would not increase the yield of sulphate. There would be no harm in having excess of acid, although this is most carefully avoided in the technical process. With a great excess of sulphuric acid the solubility is decidedly decreased, and thus the yield is increased, but then a strongly acid mother-liquor is obtained, and this is difficult to work up. If, however, phosphoric acid is present in the thorium its solvent action is diminished by the excess of sulphuric acid, which is a great advantage. In order to prevent the formation of the gelatinous 4-hydrate, which is difficult to filter, and to obtain the 8-hydrate, the temperature during precipitation must be kept below 42°. In presence of large excess of acid the formation of the 4-hydrate occurs at a lower temperature than in neutral solution. Heat of Hydration and Vapour-pressure of Thorium Sulphate Hydrates.-I. Koppel.-The author gives tables showing the vapour-pressure of Th(SO4)2.8H2O at 30° and 42°, and the heat of hydration at different concentrations and temperatures. Action of Ammonia on Mercurous Chloride.— Haridas Saha and Kumud Nath Choudhuri.-The black substance obtained by the action of ammonia solution on mercurous chloride appears to be a mixture of mercury and white precipitate. Infusible white precipitate, when freshly prepared, is soluble in concentrated ammonia, and if this solution is slowly evaporated over concentrated sulphuric acid in vacuo it crystallises out. Use of Silver in the Determination of Molybdenum, Vanadium, Selenium, and Tellurium.-Claude C. Perkins.-Molybdenum, vanadium, selenium, and tellurium can be determined gravimetrically by allowing their oxides to liberate iodine from potassium iodide in acid solution, and determining the iodine set free by making it combine with specially prepared silver. presence of alkali chloride. Lithium chloride has the Lead Coulombmeter, I.-Franz Fischer and Karl Thiele. Solutions of the lead salts of boron, aluminium, silicon, titanium, zirconium, tin, arsenic, and antimony fluoric acids were prepared and tested to see whether they could be used in a lead coulombmeter. It was found that the only ones that are applicable are lead boron fluoride, lead silicon fluoride, lead zirconium fluoride, and lead tin-The solubility of barium chloride is increased by the Influence of Electrolytes on Solubility.-W. Herz. fluoride. A method of separating tin and antimony may be based upon the formation of complexes of tin disulphide and hydrochloric acid, from which the tin is not precipitated with sulphuretted hydrogen. The mixture of salts is oxidised, and then SnS2 and Sb2S, are precipitated with sulphuretted hydrogen. The mixed sulphides are dissolved in hydrofluoric acid, and sulphuretted hydrogen is led through the solution. The antimony is then precipitated in the form of the red-brown sulphide. Concentrated sulphuric acid is added to the filtrate, and the hydrofluoric acid is driven off by evaporation. The residue is taken up with water, and sulphuretted hydrogen is led through the solution, when yellow tin disulphide is precipitated. Use of Potassium Ferricyanide in Alkaline Solution for the Determination of Arsenic, Antimony, and Tin.-Howard E. Palmer.-The method depends upon the oxidation of the oxides by means of potassium ferricyanide in alkaline solution, the equations being :As2O3+4K3Fe(CN)6 + 4KOH= = As2O5+4K4Fe(CN)6 + 2H2O, Sb2O3 + 4K3Fe(CN)6+4KOH= =Sb2O3 + 4K4Fe(CN)6+2H2O SnO+2K3Fe(CN)6+2KOH=SnO2+2K4Fe(CN)6+H2O. The ferrocyanide formed is then titrated with permanganate: 10K4Fe(CN)6 + 2KMnO4 +8H2SO4 = =10K3Fe(CN)6 + 6K2SO4 + 2MnSO4 +8H20. Iodometric Determination of Potassium Ferro- and Ferricyanide.-Werner Mecklenburg.-The method of determining potassium ferricyanide depends upon the oxidation of potassium iodide by the ferricyanide and the volumetric estimation of the iodine liberated by means of thiosulphate. The author has investigated and reports upon the conditions in which satisfactory results can be obtained. The same method can be used for the indirect estimation of the ferrocyanide. The latter can also be estimated by oxidising it with excess of 1/1ON permanganate, and determining the excess of permanganate greatest effect, and the other chlorides follow in the order: NaCl, KCl, RbCl. Sodium chloride, potassium chloride, and rubidium chloride increase the solubility of copper sulphate, while lithium chloride lowers it. MEETINGS FOR THE WEEK. WEDNESDAY, 19th.-Microscopical, 8. "Hicksonella, a New Gorgon- THURSDAY, 20th.-Chemical, 8.30. "Structure of Xanthonium and 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, 16, Newcastle Street, Farringdon Street, London, E.C. OLD PLATINUM, GOLD COVERS FOR BINDING. Oct. 14, 1910 .. net net 7 6 32 The Fundamental Principles of Chemistry. An A Text-book of Practical Physics. By W. Watson 0000 5966 ΙΟ 6 6 0 6 6 Smaller Chemical Analysis. By G. S. Newth .. 6 6 2 6 Elementary Practical Chemistry. By G. S. Newth net HALDENWANGER Can be obtained from all businesses which deal in Chemical Apparatus. London: Printed and Published for the Proprietor by EDWIN JOHN DAVEY, at the Office, 16, Newcastle Street, Farringdon Street, E.C. "October 14, 1910 Edited by AND JOURNAL OF PHYSICAL SCIENCE vir Wm. Crookes, F.R.S.] (WITH WHICH IS INCORPORATED THE "CHEMICAL gazette") Established [Sixty-seven fears Published Weekly. Annual S ibscription, free hv nost. £t. Entered at the New York Post Office as Second Class Mail matter. C Vol 102.-No. 2656. [ Friday, October 21, 1910. Registered as PRICE 44. ARTICLES: reserved CONTENTS. Annual Report of the International Committee on Atomic a Newspaper. [Post PRM 444. PAORA R.C.Sc., Mineral and Metallurgical Chemist, 199 The Origin of Cometary Bodies and Saturn's Rings, by H. Wilde 200 ... 202 23 205 205 Apparatus for the Commercial Production of Ozone ........... 207 C. PASS AND SON, LIM., BRISTOL, Are Buyers of 209 desires change. Five years Works and Mine experience Special knowledge of Tungsten, Tin, Lead, and Copper Products. Used to Rare Metal and Electro-chemical Analysis.-Address, Box 191, CHEMICAL NEWS Office, 16, Newcastle Street, Farringdon Street, London, E.C. Chemical Engineer, with French University Diploma, four years' laboratory practice, and knowledge of any Chemical Industry, wants a Position in England or abroad. Speaks Spanish and French. Address, "Engineer," CHEMICAL NEWS Office, 16, Newcastle Street, Farringdon Street, London, E.C. 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Having been established for a number of years, this would form an excellent nucleus for an extensive business.-Address," Works," CHEMICAL NEWSs Office, 16, Newcastle Street, Farringdon Street, London, E.C. The he Proprietor of the PATENT No. 17,461 of 1900, relating to "Preparing Compressed Peroxide of Sodium either Alone or with the Additiou of other Salts," desires to enter into negotiations with one or more firms in Great Britain for the grant of Licences to manufacture under Royalty.-Enquiries to be addressed to Messrs. CARPMAEL and CO., 24, Southampton Buildings, W.C. NOW READY. Cloth, 2/6. Paper covers, 3/6; THE WHEAT PROBLEM: Based on Remarks made in the Presidential Address to the British Association at Bristol in 1898. REVISED WITH AN ANSWER TO VARIOUS CRITICS By SIR WILLIAM CROOKES, F.R.S. VITH PREFACE AND ADDITIONAL CHAPTER, BRINGING THE With Two Chapters on the Future Wheat Supply of the OPINIONS of the PRESS. 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