﻿On the Theory of Chemical Potential. 483 



preted is described, and the results brought to such a form 

 that they can be compared with theory. 



16-18. The results are discussed first with reference to 

 the theory of ionization by collision. It is shown that they 

 afford considerable support for it, if the first of the two 

 alternative theories as to the nature of the negative ion put 

 forward in the previous paper is adopted. They do not 

 seem to agree with the second theory. It is concluded that 

 in dry air an electron remains an electron through most of 

 its career, and that the formation of complex negative ions 

 can only occur rarely if at all. 



18. The conclusions to be drawn from the results in the 

 matter of the speed of the delta rays is considered. It is 

 shown that they support the view that the initial speed is 

 small compared with 20 volts. 



19. The conclusions concerning delta rays which have 

 been attained in this and two preceding papers are discussed 

 with a view to the light that they throw upon the mechanism 

 of ionization. 



It is, of course, clear that the brief discussion given of 

 the mechanism of ionization is largely due to the suggestions 

 of Prof. Bragg, to whose inspiration all this work is due. 



Leeds University, Nov. 18, 1911. 



— 



XLV. On the Application of the Theory of Chemical Potential 

 to the Thermo dynamical Theory of Solutions. By S. A. 

 Shorter, P.Sc, Assistant Lecturer in Physics in the 

 University of Leeds. — Part II. The Effect of Pressure on 

 Vapour - Pressure. The Vapour - Pressure Theory of 

 Osmotic Pressure. The Freezing of Solutions *. 



IN a previous communication f we considered the equi- 

 librium between the solution and solvent vapour in the 

 case where the surface of separation is plane, and the pres- 

 sure, therefore, the same in both phases. If the surface of 

 separation is curved, the pressures in the two phases will 

 differ by an amount equal to the product of the surface 

 tension and the total curvature, and the conditions of equi- 

 librium will, of course, be modified. We may also suppose 

 this co-existence of the two phases to be brought about by 

 means of an insoluble gas. This involves the introduction 

 of the idea of partial pressure, as well as the assumption of 



* Communicated by the Author. 



t Phil. Mag. xxii. p. 933, Dec. 1911. The author takes this opportunity 

 of making the following corrections in Part I.: — page 934, line 17 from 

 top, for S read s: page 938, line 6 from bottom, for P (s, po } 6) road 

 PqO,A0). 



2 K 2 



