846 Dr. R. W. Boyle on the 



For example, in a determination at 14° C, 



A=33'18c.c. 



V=12-2 „ 



»i= 1-29 „ 



r 2 = 10*73 „ 



r= 6-50 

 Thus S.= 0-306. 

 In Method 1, without very appreciable errors, r,:=V 5 

 r 2 = 0, and T=A + B; similarly, in Method 2 v 2 = B. The 

 ratio r mast be measured very correctly for use in the 

 formulas above, more especially in formula 1, where dif- 

 ferences appear in the numerator and denominator of the 

 expression for 8. The quantities V, ?' l5 and r 2 can be quickly 

 and conveniently determined by separately weighing the 

 bulbs before and after placing them in the temperature barh, 

 and subtracting the respective weights of the empty bulbs. 

 The specific gravities of the absorbing liquids must be known 

 or must be determined. 



Method 1 — the sampling of the gas-phase — is more suitable 

 when the gas takes a greater share of the emanation than 

 the liquid, that is, generally speaking, when the coefficient 

 is less than unity. This is the case of water and of aqueous 

 solutions of salts. 



Method 2 — the sampling of the liqnid-phase — is better 

 used when the liquid takes the greater amount of emanation. 

 This is the case of many organic liquids. By choosing the 

 more suitable method, errors due to the mechanical suspension 

 of drops of liquid in the gas-phase, or of bubbles of gas in 

 the liquid-phase, may be minimized. Also, after a few trial 

 experiments, it is possible so to select the sizes of the bulbs 

 and the amount of absorbing liquid as to have nearly the 

 same quantity of emanation in both mixing and sampling 

 bulbs. This makes it possible to obtain nearly eqnal rates of 

 movement of the gold-leaf in the electroscope, and thus avoid 

 possible instrumental errors. 



In the case of water below T ordinary temperature, the two 

 methods agree very well, as is shown in the examples already 

 given, and in the following which refer to 0° 0. : — 



By Method 1. 



By Method 2. 



A = 37-21 c.c, 



A = 33'17 c.c 



B = 25-76 „ 



V = 20-39 ., 



A^=18-60 „ 



i\= 9-22 „ 



v x ~ 18*55 „ 



r 2 = 10'81 „ 



r 2 = 0-02 „ 



r= 3-17 



k= 0-416 





r= 1-585 





.-. S= 0-500 



.•'. ^S= 0-511. 



