208 THE ROYAL SOCIETY OF CANADA 



solvents, with a view to discovering, if they exist, cases of equilibrium 

 analogous to the distribution of iodine between ether and water. It 

 seemed a priori probable that such equilibria would most likely be met 

 with in the case of colloids with marked power of diffusion, and immis- 

 cible solvents which approach each other closely in properties and 

 composition, such as those near the "critical solution temperature" 

 in two-component systems, or the solutions near the plait-point of the 

 binodal curve in three-component systems. 



The Winkelblech effect (coagulation of the colloid at the boundary 

 between the solvents) interfered with the observations in the case of 

 silver hydrosol and phenol, amyl alcohol, or isobutyl alcohol; two ex- 

 periments shewed the dependence of the Winkelblech effect on ca- 

 pillary forces. 



Chloroform and alcohol did not coagulate the hydrosol of arsenious 

 suljDhide, but no distribution was observed even at the plait-point; 

 this is not due to "passive resistance." The same is true when the 

 alcohol was replaced by acetone; but if ether or ethyl acetate were 

 substituted for the chloroform distribution readily occurred, whether 

 alcohol, acetone or propyl alcohol was employed as consolute liquid. 

 In this connection a rapid method of determining the binodal curve, 

 tie-lines, and plait-point was worked out. 



Antimony trisulphide, like the sulphide of arsenic, distributed 

 between the two liquid phases in the system water-ether-alcohol; 

 but not in the system water-chloroform-alcohol. Copper sulphide 

 did not distribute in the system water-ether-alcohol. (Jour. Phys. 

 Chem. 12, pp. 706-716, 1908). 



No. 3. W. Lash Miller: — The theory of the direct method of deter- 

 mining transport numbers. The impression has gained ground among 

 experimental workers in this field, that "directly" determined transport 

 numbers need not necessarily agree with those determined by Hittorf's 

 method. The theory of the direct method was first developed by 

 Kohlrausch from equations involving the mobilities of the ions concerned; 

 it is possible, however, to avoid all reference to rates, mobilities, current 

 and other functions involving time, and to shew that transport numbers 

 properly calculated from observations of the movement of the meniscus 

 must be identically the same as those obtained from the analytical 

 method; in fact, that the meniscus method is but a modification of the 

 method of Hittorf, in which the amounts of the various constituents 

 of the solution transported are determined by volume measurements 

 instead of by quantitative chemical analysis. {Zeit. phys. Chem. 69, 

 pp. 436-441, 1909). 



No. 4. J. D. Barter: — The sulphates of barium. Freshly precipitated 

 barium sulphate was washed several times with sulphuric acid and 



