482 THE ANALYST. INORGANIC ANALYSIS. An Investigation of Fuller's Earth. (Chem. Rev. Fett- u. Hurx-Ind., 1908, 15, 253-255.)-Analyses of the minerals with which Fuller's earth may be associated lead to the conclusion that it is a decomposition product of hornblendes and augite, and not, like ordinary clay, of felspars. This view is supported by the fact that magnesia is invariably an important constituent of fuller's earth, in which it is as a rule present in much greater proportion than in ordinary clays. This is shown in t h e following table of analytical results given by different kinds of fuller's earth, the figures being collated from various sources, and calculated on the dry substance. Origin. Arkansas ... ... Ocala, Florida ... Gladsden, Florida . . , Norvay, Florida ...Decatur, Georgia ... Enid, Oklahoma (glazialite) ...} Custer, South Dakota ... ... Fairburn, South Dako ta... ... Nutfield, England (blue earth) ...} Nutfield, England ) (yellow earth) . . . J Reigate, England ... Woburn Sands, England (yellow earth) ... ... Woburn Sands'Eng- land (blue earth) } Silica. Per Cent. 64-38 39.66 67.31 59-02 72'00 50.36 57.00 68.23 52-81 6S.37 53.00 55'48 60.90 klnmina. Per Cent. 17.29 30.00 11 -07 11-88 10.76 33'38 17-37 14-93 6 -92 11.82 10.00 19.16 18'34 Water. Per Cent 6 *95 13.11 8.25 11'13 6.00 12-00 9 -50 6 *20 14.27 13'19 24-00 6 -75 4 -89 Ferric Oxide. Per Cent. 8.27 3.46 2-61 7.24 2-65 3-31 2.36 2.15 3-78 6.27 9.75 11.78 10'22 I Magnesia. I ?er Cent. I Per Cent. 1.91 0.87 2'60 6-48 3.34 - 3.00 2.93 7-40 6.17 0 5 0 3.10 2-36 0.70 3.32 3-24 4-36 - 3-03 0.87 2.27 2.09 1-25 3-71 1 -52 Alkalies.?er Cent, 1 '83 0.45 1.01 - - 0.88 __ - 1 -74 1.84 - - 1'72 Other Elements. Per Cent. - P,O,, 6-00 Oi*,qaiiic mat- ter, 3-90 no,, 1.37 - - - TiO,, trace Organic mat- ter, trace Volatile snh- stances, 5 '8 5 Volatile sub- stances, 5 -85 - P,O,, 0.27 SO,. 0.05 NaC1, 0.05 P,O,, 0.14 SO,, 0.07 N'aC1, 0'14 - - - C. A. M.THE ANALYST, 483 Volumetric Estimation of Potassium Ferrocyanide. H. Bollenbach. (Zeits. anal. Chem., 1908, 47, 687-690.)-The solution of potassium ferrocyanide is strongly acidified with dilute sulphuric acid, and standard potassium permanganate solution added until a decided red colour is produced. After adding a few drops of a solution of ferric sulphate, the excess of permanganate is estimated by adding & potassium ferrocyanide solution until a permanent greenish-blue colour is produced ; the addition of 1 drop of the permanganate solution should destroy this colour.The method is accurate to within 1 per cent. of the ferrocyanide present. A. G. L. Suitability of Commercial Ammonium Swlphate as Manure. F. J. Lloyd and U. Bonelli. (Chem. Trade Journ., 1908, 43, 362.)--Although commercial am- monium sulphate now rarely contains any appreciable quantity of thiocyanates, many samples are contaminated with organic compounds (coal-tar derivatives) which in the opinion of the author have an injurious action on plant life. In order to distinguish between these and the innocuous organic matter present in “ bone sulphate” the authors apply tho following test : One gram of the sample is dissolved in 5 C.C.of water and strong ammonia added. A violet coloration is produced in the presence of the undesirable organic compounds, no such colour being obtained with 6‘ bone sulphate ” or pure 66 gas sulphate.” Since these organic hubstances tend to obscure the usual reaction for thiocyanates, the best method of applying the test is to dry 5 grams of the sample, after moistening with strong ammonia, in the water-oven, grind it in a mortar with 5 C.C. of alcohol and filter, and test the clear filtrate with ferric chloride. A. R. T. Volumetric Estimation of Phosphoric Acid in Fertilisers. R. Williams. (Chem. Engineer, 1908, 8, 97-99.)-The American official volumetric molybdate method for the determination of phosphoric acid in acid phosphates and commercial fertilisers (Bull.No. 107, Bureau of Chemistry, U.S. Department of dgricultu;?.e) is open to serious objections, among which may be mentioned-(1) the erroneous results due either to the presence of sulphates in the material or to the use of sulphuric acid as a solvent, sulphates causing a precipitation of molybdic acid in excess of the thgoretical amount necessary to combine with the phosphoric acid present; and (2) the presence of arsenic in the fertiliser. The author therefore first separates the total phosphate by precipitating an aliquot portion of the acid solution of the material (equal to from 0.1 to 0.4 gram sample), containing as little excess of acid as possible, by the addition of 1 C.C. of mixed ferric and calcium chlorides (10 per cent.of each in solution), and sufficient ammonia to render the solution slightly alkaline. One hundred and fifty C.C. of boiling water are next added and the settled liquid filtered, the precipitate washed once with hot water, and then dissolved in 100 to 125 C.C. of hot dilute nitric acid (70 C.C. strong acid in 1 litre). The solution is nearly neutralised with ammonia, precipitated with 30 to 35 C.C. of the molybdate solution added to the rotated hot liquid, and the process then carried out as directed in the official method (loc. cit.). A. R. T.484 THE ANALYST. Analysis of a Mixture of Neutral Sulphides, Acid Sulphides, Poly- sulphides, and Hydrosulphites. F. Dhuique-Mayer. (Rev. gher. Chin&. pure appl., 1908, 11, 273-274; through Chem. Zed. Rep., 1908, 32, 485.)-Ten C.C. of the 6OlUtiOn are diluted to 100 C.C. with water. Ten C.C. of this diluted solution are titrated with sulphuric acid, using phenolphthalein as indicator. The value obtained (A C.C. & solution) corresponds to the neutral sulphides present. The same solution is then titrated with iodine solution and starch, giving a value I. After decolorising the solution by adding a few drops of the diluted origintll liquid, sodium hydroxide is added until the solution becomes pink, giving a value R, which corresponds to the total acid sulphide formed in the solution. Another 10 C.C. of the original solution is diluted, treated with 2 grams of lead carbonate, filtered, and titrated with iodine solution and starch, the value H obtained corresponding to the hydrosulphite present. The acid sulphide originally present in the liquid equals (R - A) ; the polysulphide corresponds to (I - 2R - H). A. G. L.