844 Dr. R. W. Boyle on the 



quickly established, the bulbs were left in the temperature 

 bath for an hour or more (sometimes as much as two or three 

 hours), and very frequent shakings were given. This length 

 of time in the bath ensured that the absorbing liquid had 

 taken up the proper temperature. After shaking, the bulbs 

 were allowed to stand in the bath for ten minutes, which 

 allowed the bubbles of gas suspended in the liquid to come 

 to the surface. 



From this point on an experiment may be proceeded with 

 in one or the other of two ways. 



Method 1. Holding the bulbs vert : cally in the bath, with 

 the sampling bulb uppermost, the interiors of the two bulbs 

 are put in connexion by opening the stopcock of the mixing 

 bulb. The gas in this bulb then expands and occupies the 

 free space of the two bulbs together. The two stopcocks are 

 then shut, thus enclosing the contents of the respective bulbs. 

 Method 2. With the bulbs vertical and the mixing bulb 

 uppermost, the stopcock of the mixing bulb is opened, thus 

 allowing the liquid inside it to be forced by the pressure of 

 the gas above into the lower, evacuated, bulb. r Jhe volume 

 of the absorbing liquid u«ed should be, preferably, just a 

 little more than the volume of the sampling bulb and con- 

 nexions, so that the sampling bulb can be completely filled. 

 After this expulsion of liquid both stopcocks are closed. 



Both the operations just mentioned take place in a second 

 or two, so that there is no time for the emanation to stream 

 out of the liquid and form a new equilibrium. When the 

 stopcocks are closed, the bulbs are taken from the bath and 

 disconnected by removing the pressure-tubing. The end 

 tubes are dried out with blotting-paper, and the bulbs are 

 set aside for at least four hours, after which their emanation 

 contents are measured by means of the 7-ray electroscope. 

 The coefficients of solubility are calculated as follows : — 

 Let A = vol. of the mixing bulb, 

 B = vol. of the sampling bulb, 

 T = total vol. of both bulbs plus their connexions, 

 V = total vol. of absorbing liquid used, 

 i^rrvol. of absorbing liquid left in the mixing bulb 



after the experiment, 

 z? 2 = vol. of absorbing liquid found in the sampling 



bulb after the experiment, 

 r = the ratio of the emanation in the mixing bulb to 



that in the sampling bulb after the experiment, 

 c = the emanation per c.c. of the gas in the mixing 



bulb before expansion, 

 S = the coefficient of solubility. 



