[miller] researches IN PHYSICAL CHEMISTRY 27 



Finally, the oxidation-potential of mrta-nitraniline in decinormal 

 sulphuric acid was deteraiined, and found to be 1 '4:?> volts. 



6. A Mechanical Model to illmtrate the Ga-^ Lairs: — Dr. Frank 

 B. K enrich. The difficulty of getting elementary students to grasp 

 the fundamental ideas of the gas laws confronts every teacher of physical 

 chemistry. The model, which has been in use for a year in the 

 chemical laboratory of the University of Toronto, works admirably, not 

 only in giving students definite conceptions of Carnot's cycle, etc., but 

 also in awakening their interest in, and aiding them to grasp the 

 essential idea of the calculus. (Described in Jour. Pbys. Them. VIIT., 

 351). 



7. The Determination of Phenol; and tlie Del cet ion, Estimation, 

 and Rate of Formation of Tri-hrom-phenol-hromide : — Mr. S. J. Lloyd. 

 It is first shown that the liberation of iodine from hydriodic acid by 

 tribromphenol-bromide is not quantitative, from which it follows that 

 the formation of the bromide in the determination of phenol by bromine 

 vitiates the results of the analysis. The conditions under which the 

 bromide is formed are then taken up, and means of obviating its occurr- 

 ence discovered; in this connection a solution of benzidine in chloroform 

 was found to serve as a delicate qualitative reagent for tribromphenol- 

 bromide, and a method for estimating it quantitatively was worked out. 



Experiments on the evaporation of bromine during the analysis, 

 and on the action of bromic acid on plienol complete the investigation, 

 which results in formulating the conditions under which phenol can be 

 determined with an accuracy of 1 to 3 parts per thousand. 



8. The Electrolytic Migration in solutions of the weak acids: — Mr. 

 J. W. McBain. Continuing his work of last year, with the assistance 

 of a grant from the Carnegie Institution of Washington, Mr. ]\[cBain 

 has determined the migration in n/2, n/10, and n/50 acetic acid in 

 n/10 propionic acid, and in mixtures of acetic acid with sodium acetate 

 and with hydrochloric acid. He has also studied the motion of acetone 

 in solutions containing water, acetone and cadmium sulphate. 



9. An apparatus for the quantitative study of the action of 

 chemicals on Bacteria at constant temperature : — Prof. W. Lash Miller 

 and Prof. J. J. MacKenzie. The experiments described last year (these 

 Transactions, IX., 51) are being continued with improved apparatus, 

 by means of which the phenol solutions can be inoculated and samples 

 removed (to count the bacteria) without removing them from the 



