proceedings: chemical society 341 



number of theories in addition to those he had given had been suggested 

 for these potentials, and the subject is still unsettled. The fact remains 

 that if the semipermeability of the membrane is destroyed, the potential 

 difference is lowered or disappears. To an inquiry by Berg, as to the 

 bearing of certain experiments on the injection of lecithin-saturated 

 ether upon the theory, it was replied that these experiments do not 

 settle the point. Gore inquired as to the effect of calcium salts. 



The 226th meeting was held at the Cosmos Club on Friday, May 2, 

 1913. 



Prof. Eugene C. Bingham, of Richmond College, Richmond, Va., 

 spoke on the subject, Fluidity and its relation to other physical and 

 chemical properties. Viscosity and fluidity were first defined, and their 

 analogy to electric resistance and conductance brought out. The evi- 

 dence shows that fluidities and not viscosities are additive. For this 

 reason the relation of fluidity to temperature approaches a straight 

 line. Liquid emulsions and solid suspensions, as well as mixtures of 

 liquids, have been studied by the author. In the case of emulsions, 

 viscosity tends to be additive, as expected. In suspensions, zero fluidity 

 appears at a percentage composition far below that at which the mix- 

 ture ceases to flow visibly. This composition is believed to represent the 

 dividing line between viscous and plastic flow. In accordance with 

 theory, the zero of fluidity is independent of the liquid and of the tem- 

 perature. The lecturer then showed many examples of the use of fluid- 

 ity curves in interpreting the constitution and relations of mixtures of 

 organic liquids, for instance, the indication of a compound between 

 ether and chloroform. The lecture was illustrated by lantern slides 

 and experiments. 



Discussion. Sosman inquired whether a crystalline compound of 

 ether and chloroform is known, corresponding to that shown bj' the 

 fluidity curve. Professor Bingham knew of none. In reply to inquiry 

 by Ford, as to why the curves of zero fluidity were not carried nearer 

 zero. Professor Bingham stated that the solid settles out and closes the 

 capillary. Bunzel mentioned the application of these facts to milk 

 and casein suspensions. The discussion led into the question of the 

 cause of emulsification by dilute alkaline solutions; Professor Bingham 

 beheved this due in part to the formation of films from the fatty acid 

 or saponifiable oil which might be present. Ford quoted experiments 

 of Spring in opposition to this view. In reply to a question by Berg, 

 it was stated that the condition of the surface of the soHd does not 

 affect the value of fluidity obtained. In support of Professor Bingham's 

 view Berg quoted the fact that olive oil, when entirely free from acid, 

 is not emulsified by soda, altho it becomes emulsifiable on standing in 

 air. Sosman mentioned the reciprocal relation of density and volume 

 as similar to that of viscosity and fluidity, and spoke of some miscon- 

 ceptions that have arisen because density, instead of volume, was 

 assumed to be the additive property. 



C. L. Parsons gave a brief report on the Milwaukee meeting of the 

 American Chemical Societj-. 



