﻿- 3 + 



Pi 



»_»_ 6 + 2e= 24(«l_Mr , (26) 



18 Mr. W. Sutherland on «/ie Molecular 



the second, 

 « = ^2 + 24 ( 54t/4 _ 4 \ _ a] + 4 ) + 



Li 6- V/oi /o 2 / /o 2 j°4J P2 e \pi p 2 'J 

 By comparing this and (21) we obtain the desired relations, 

 remembering that in (21) p 4 is the amount of solute in a 

 gramme of the bulk solution. Let p± in the surface equal k 

 times p± in the bulk, then we have 



c _ a , = 4|54r/4_4\_4 + 4u _ . _ _ (u) 



Pi P2 [ e \pi p 2 ! p 2 pi I 



6 _ 2c= r(Mi(4_4\_4 + 4| 2 _24/4_4\54xn R 



L I e \pi pj p 2 Pi) P2\pi P2J e A 



In these equations a 3 , p d refer to pure water, and for tem- 

 peratures below 40° C. may be identified with a 2 , p 2 . So 



«2IP 2 2 \2 a 2 , , 2af 



5/>, / • P\ P2 \Pl P2 



With the values of b and c from Table III. of " Mol. Force 

 and Surf. Tension of Solutions " (loc. cit.), identifying surface 

 p with bulk p and taking a 1} a 2} pi, p 2 from " The Mol. Const. 

 of Water," we can use the last equations for calculating rk 2 

 (surface) for various solutions, and then (24) gives ajpl for 

 the solute. The surface tensions are expressed in milligrammes 

 weight per millimetre. In this unit a x = 7*73 and # 2 = 7'44 

 at 20°, while /o, = l'07, |° 2 = 0'877. 



Table V. 



NaCl. KC1. NaN0 3 . KN0 3 . MgCl 2 . CaCl 2 . SrCl 2 . BaCl 2 . 



100c 361 380 270 333 290 271 170 180 " 



1006 647 380 460 313 650 667 416 120 



lOOrF (surf.). . 170 100 110 130 165 200 240 105 



100r (bulk) ... 57 68 69 80 99 96 106 104 



t7c 2 /t 30 1-4 16 1-6 1-7 21 2-3 1-0 



Na 2 C0 3 . K 2 C0 3 . Na 2 S0 4 . K 2 S0 4 . MgS0 4 . ZnS0 4 . CuSO,. 



100c 80 180 180 160 80 20 20 



1006 910 668 550 1820 790 520 730 



100rfc( S urf.).. 320 290 250 950 320 320 410 



lOOr(bulk) ... 171 182 103 114 145 152 



rk*/T. 1-9 1-6 2-4 8-4 2-2 21 — 



