THE ANALYST. 31 INORGANIC ANALYSIS. Gasometric Determination of Copper by Means of Hydrazine Salts. (Zeds. nno7-g. Chem., 1905, vol. 47, p. 371.)-Ammoniacal salts of copper E. Ebler. are quantitatively reduced by hydrazine salts according to the equation- 4Cu(NH3),S0,+ N,H,.H2S0, = 2Cu,(NH3),S0, + N, + 2NH3+ S(NH,),SO,, the whole of the nitrogen present in the hydrazine being evolved as gas. The reaction is suited both for the determination of copper and of hydrazine, is carried out in the apparatus, devised by €Iempel,:t: which is shown in the figure set up ready for use. If copper is to be determined, the copper salt is placed in the flask R, together with an excess of aqueous ammonia. The flask and condenser are then exhausted through k, attached to a filter-pump ; the tap n is closed, and a solution of hydrazine sulphate is added from the funnel T until the blue colour is dis- charged, communication with the flask being established by slightly lifting the tube k, the expanded end of which acts as stopper for T.The contents of the flask are boiled until several C.C. of water have been condensed in the burette. It is advisable to use mercury and not water in the burette, as there is a possibility of nitrous oxide being formed instead of nitrogen, although the author has never found this to be the case. The nitrogen is fhen measured as usual ; 1 C.C. at 0” C. and 760 mm. corre- sponds to 11.31 mgm. of copper. The procedure for determining hydrazine by means of an ammoniacal solution of copper is similar. If mercury and silver, which interfere with the determination of copper, &re present, they may be removed by treating the ammoniacal solution of all three metals with hydrazine sulphate or hydroxylamine chloride ; the reduced solution of copper is filtered from the precipitated mercury and silver, evaporated with nitric acid to destroy the excess of precipitant, again evaporated with hydrochloric acid to remove nitric acid, and then treated as above.I n both cases the results are good. A. G. L. * “ Gasa.nalytisclie Blethode,” 3 Auflage, Seit. 62.32 THE ANALYST. The Gasometric and Volumetric Determination of Mercury by Means of Hydrazine Salts, and the Gasometric Determination of Hydrazine by Means of Mercury Salts. E. Ebler. (Zeits. anorg. Chew., 1905, vol. 47, p. 377.)-The author shows that in aqueous acid or amtnoniacal solution mercury salts react with hydrazine salts according to the equation (neg- lecting ammonium salts)- 2HgC1, + K,H, = 4HCl+ 2Hg + N,.The reaction is carried out at boil- ing temperature in the apparatus shown in the figure, the exit tube (H) being connected to a Schiff nitro- meter. Either concentrated solutions containing a little hydrochloric acid and an excess of sodium acetate, or else somewhat more dilute am- moniacal solutions, are used. The results, both for mercury and for hydrazine sulphate, are, on the whole, satisfactory. Another method of determining mercury by means of hydrazine con sists in adding a known amount of $; hydrazine sulphate to the am- moniacal mercury solution, which should contain ammonium chloride, --------x heating on a water-bath until the precipitated mercury has settled, making the whole up to a, known volume, and titrating aliquot parts of the filtered solution with & iodine, after adding hydrochloric acid and bicarbonate, the reaction between iodine and hydrazine being N,H,.H,SO, + 41 = 4HI + H,SO, + N,.The results obtained in this way are good. Silver and copper, both of which also reduce hydrazine, may be removed, the former as chloride, and the latter by precipitating the mercury from ammoniacal solution by hydrazine, copper remaining in the solution in the cuprous state. The mercury is then converted into chloride as usual, and this salt is treated as above. A. G. L. Further Communication on Simplified Methods of Estimating Potash.(Clzem. Zeit., 1905, xxix., 1085.)-A fairly lengthy paper, the main F. Klinkerfues.THE ANALYST. 33 points of which only can be given here. The author has given an account of his process (vide ANALYST, 1905, xxx., 172). He now makes some further observations on the method. The method does not require the previous removal of sulphates and phosphates. The evaporation with formic acid need not be continued to dryness, but only until reduction of the platinum is complete. Finally, it is urnecessary to dissolve the washed double salt in hot water, but the salt can be washed into the platinum dish and the formic acid added at once. This only requires a small amount of liquid. The author has also investigated the estimation of nitrogen in potash free ammonium salts by this method; the same degree of exactness is attained as for potash, and the minimum error is not more than 2 mgms.of platinum. This does not depend on the amount; of substance taken, but is the unavoidable error of weigh- ing; consequently it is possible, by choosing the quantity of substance used, to make the percentage error as small as may be desired. One gram Pt correspond to 0.1441 grams N. The author then applied the method to the estimation of potassium in presence of ammonium, substracting the weight of platinum due to the nitrogen (found by an independent process) from the total weight obtained, and thence calculating the potash. The results obtained, however, for potassium ammonium superphosphate were too high, and the author reserves his opinion of the reason for this until he has completed more analyses.Potash free ammonium superphosphate gave exact results. The author, in the meantime, uses the following process for the mixed super- phosphate : The nitrogen is estimated in the ordinary manner, by distilling off the ammonia with potash free magnesia or soda, and the residue in the distillation flask made up to a known quantity ; the potash is estimated in a known fraction by the author’s process. Finally, a vacuum dessicator can be dispensed with, as it is immaterial whether the platinum is cooled in vacuo or not. E. K. H. Determination of Sulphur in Pyrites. G. Lunge. (Zeits. angew. Chem., 1905, xviii., 1656.)-Dennstedt and Haszler have recently stated (Zeits. angezu. Chem., xviii., 1562) that some basic ferric sulphate may remain undissolved if Lunge’s directions relating to the treatment of the residue left on evaporation with ( 6 1 C.C.of concentrated acid and 100 C.C. of water” are followed. Lunge now claims that he never meant this to mean that the residue was to be treated with the mixture of acid and water, and that he himself always treats first for a short time with 1 C.C. of hydrochloric acid, and only then adds the 100 C.C. of water. A. G. L. Estimation of Sulphur in Iron. J. Petren. (Chewz. Zeit., Rep., 1905, xxix., 324.)-The author has investigated the various standard methods. He finds that those methods in which the sulphur is oxidized to sulphuric acid direct, without any separation from iron give the most exact results, but are the most lengthy; those in which sulphuretted hydrogen is evolved are quick and accurate enough for ordiuary technical work.E. K. H.34 THE ANALYST Preparation of Phosphorus Di-iodide. Howard W. Doughty. (Jozwu. Anzer. Chem. Xoc., 1905, xxvii., 1444.)--A flask containing a mixture of 50 grams of iodine and 4 grams of red phosphorus is heated over a naked flame until its contents are thoroughly melted. I t is then allowed to cool to 60" C., and 2.5 grams of yellow phosphorus in small pieces are added, when the mass will become solid. The method is stated to be quick and safe. -4. G. L. APPARATUS. " Continuous - Flow " Wash Bottle.-By means of this arrangement a continuous flow of liquid may be obtained for washing precipitates, etc. I n action it is exceedingly simple. The hole A is covered by the thumb, and air blown into the mouth-piece until a certain pressure is induced in the flask. On ceasing to blow, sufficient air is retained by valve B to force a stream of liquid for a short time through the jet, The cur- rent stops immediately the thumb is removed from A-in fact, so suddenly that the apparatus may be used for filling small measures, etc., to a definite volume. It is manufactured by Messrs. J. J. Griftin and Co., London. A - -- W. J. S.