726 REPORT— 1893. 



the peroxide, followed by permanganate, is in most cases about equal to that 

 obtained when tbe water is distilled with alkaline permanganate alone. There 

 appears to be no ratio between the quantities of ammonia evolved by the two re- 

 agents, and therefore the nitrogenous organic matter present in waters might be 

 divided into two classes, viz., that which is oxidised by the sodium peroxide and 

 that which resists such treatment. The results obtained by Wanklyn's process, as 

 compared with the total nitrogen present in a water, also show a differentiation in 

 the organic nitrogen substances present in waters, but this knowledge has hitherto 

 not been of any value owing to the complex nature of the problem. Further 

 experiments can alone decide whether the limited oxidation of the nitrogenous 

 matter in waters will throw any fresh light on the condition of these organic con- 

 stituents of water. We have, however, noticed that in some cases a water which 

 lias been partially oxidised by the peroxide yields the remainder of its ammonia to 

 the alkaline permanganate with much greater rapidity than when the water has 

 not been so treated. We suggest that the explanation of this phenomenon may be 

 due to the presence in waters of organic nitrogenous substances which, when 

 partially oxidised, are then in a condition to be completely broken up by the 

 stronger reagent. This result has been obtained with waters containing fresh 

 sewage, but we hope by taking solutions containing nitrogenous compounds of 

 known constitution to confirm this suggestion, and to show that in this reagent 

 we have an oxidising agent which will be useful in establishing the constitution 

 of the nitrogen in complex organic substances. 



TUESDAY, SEPTEMBER 19. 

 The following Reports and Papers were read : — 

 1. Report on Isomeric Naplitlialine Derivatives. — See Reports, p. 381. 



2. On the Application of Electrolysis to Qualitative Analysis. By Charles 

 A. KoHN, Ph.D., B.Sc, Lecturer on Organic Chemistry, University 

 College, Liverpool. 



Since the publication of C. Bloxam's papers on ' The Application of Electro- 

 lysis to the Detection of Poisonous Metals in Mixtures of Organic Matters ' ^ 

 little has been done to apply this method of analysis to qualitative investigations, 

 despite the fact that Classen and his pupils, together with E. F. Smith and others, 

 have made rapid advances in electrolytic methods of quantitative analysis. Many 

 of these later methods offer special attraction for qualitative work, especially in 

 cases of medical and of medico-legal inquiry. They are not supposed to supersede 

 in any way the ordinary methods of qualitative analysis, but to serve as a final 

 and crucial means of identification for the more important mineral poisons. The 

 applicability of the methods for the detection of antimony, mercury, lead, copper, 

 and cadmium has been examined. The method originally devised by Bloxam for 

 the detection of arsenic has been more recently elaborated by Wolff, who has 

 succeeded in detecting O'OOOOl grm. of arsenious acid electrolytically. 



Antimony. — The method employed is that used in the quantitative estimation 

 •by electrolysis, a method devised by Classen, and which ensures a complete separa- 

 tion from antimony and tin. The precipitated sulphide is dissolved in potassium 

 sulphide, any polysulphides present oxidised with hydrogen peroxide, and the 

 solution electrolysed with a current of l"5-2'0 cc. of electrolytic gas per minute 

 (10'436 c.c. at 0° and 760 mm. = 1 ampere), a small circular piece of platinum 

 1 cm. in diameter being employed as the cathode. The deposited metal can be 

 confirmed for by evaporating a little ammonium sulphide on the foil. One part of 



> J. Chem. Soc, 13, pp. 12 and 338. 



