98 REPORTS ON THE STATE OF SCIENCE. 



combine. On the one hand this compound attacks anilines, forming 

 nitroamines, and not acetyl derivatives, and on the other hand this 

 compound does not react with water more rapidly than acetic anhydride 

 itself. 



The Committee desire to be reappointed for the coming year, and 

 ask for a grant of 15Z. 



Electroanalysis. — Report of the Committee, consisting of Professor F. S. 

 Kipping (Chairman), Dr. F. M. Perkin (Secretary), Dr. G-. T. 

 Beilby, Dr. T. M. Lowry, Professor W. J. Pope, and Dr. 

 H. J. S. Sand. (Draicn up by Dr. H. J. S. Sand.) 



Attention has been directed during the past year particularly to the 

 application of the electrometric method to the titration of weak acids in 

 such liquids as tan liquors. It was found that the potentiometer-box 

 and auxiliary electrode constructed for the separation of metals by 

 graded potential may be conveniently employed for this purpose in 

 conjunction with a form of hydrogen electrode specially designed to 

 combine ease of manipulation and rapidity of saturation. The ques- 

 tion regarding the ' end-point ' of the titration has been examined. It 

 is known that if the object of the titration he to determine the number 

 of equivalents of acid present, then not only the nature of the acid or 

 acids must be considered but also the concentration of the salts result- 

 ing from the titration. It has been pointed out, however, that in most 

 practical cases it will be possible to fix end-points of special importance 

 for the particular purpose in question. Frequently the liquid may be 

 titrated until the hydrion-concentration of pure water is reached. 

 This corresponds to a potential difference between the hydrogen-elec- 

 trode and the normal calomel electrode recommended for these titrations, 

 of 0-69 volt, 1 



By Dr. F. Mollwo Perkin. — It has been found possible by Hilde- 

 brand - and E. F. Smith and his co-workers to electrolyse the alkali 

 metals with a mercury cathode and to analyse both the anion and 

 cation. For this purpose a double cell is employed, the inner and 

 outer portion being sealed by means of mercury. The alkali salt to be 

 analysed, say potassium sulphate, is placed in solution in the central 

 cell where an anode of platinum gauze is rapidly rotated. The outer 

 cell contains water with a small quantity of sodium chloride solution 

 to make it conductive. On electrolysing, the S0 4 anions are discharged 

 at the anode and a solution of sulphuric acid obtained. The K 

 cations are discharged on the mercury which is made the cathode. 

 Owing to the rotation of the anode the amalgam, which is specifically 

 lighter than the pure mercury, is swept into the outer compartment 



1 See Part I. Journ. Soc. Chem. Ind. (in conjunction with D. J. Law), 1911, 30, 3 ; 

 reprinted in full Journ. Amer. Leather chemists Assn., 1911, 114; and Ledermarkts 

 Kollegium, 1911, p. 150, Part II. (in conjunction with J. T. Wood and D. J. Law), 

 Journ. Soc. Chem. Ind., July 31, 1911. 



2 Chem. Zentralblat., 1907, ii., 8. 



