216 



38 



==^ 



from vents in the dry, porous soil. In every case the method emploj'cd in eollcel- 

 ing spring gases was the same as that described by Travers, as shown in Fig. 7. 



The gas emanating from the spring was gathered 

 up by the [enamelled funnel, T, and conducted 

 through a tin tube into the collecting bottle. The 

 pressure acting uj)on the gas collected in the funnel 

 was great enough to force the gas through the 

 connecting tubes and the collecting bottle. Care 

 was taken that the gas, after having passed through 

 the collecting bottle, always bubbled through water, 

 in order to make sure that atmospheric air could 

 not by any means be introduced into the collect- 

 ing bottle. In order to facilitate the exclusion of 

 atmospheric air from the collecting bottles in the 

 beginning of the experiment, they were filled with 

 water and then connected with the conducting 

 tubes, out of which the atmospheric air is driven 

 beforehand by the current of spring gas. The flow 

 of the water from the bottle was regulated bj' 

 means of stop-cocks according to the evolution of 

 the spring gas, so that we were sure that the pressure of the gas above the water 

 in the collecting bottle was never lower than the atmospheric pressure; had this 

 been so, it would have caused the water from the funnel to be sucked up into the 

 conducting tubes. 



Fig. 8 A shows the kind of bottle in which the spring gas to be 

 examined for radioactivity was collected. Every bottle is provided 

 with two tubes capable of being closed airtight by means of the 

 stop-cocks a. I took with me on the journey 8 sets of these 

 bottles, each set consisting of two bottles, one containing 100 ccm. 

 and the other 200 ccm. The bottles were provided with etched 

 numbers, and before the journey they were measured by weighing 

 them filled with water. 



As already mentioned two samples of spring gas, 100 ccm. 

 and 200 ccm., were collected from each hot spring investigated. 

 In order that the gas in the samples might be as homogeneous 

 as possible, the two samples were collected simultaneously by 

 connecting the collecting tubes parallel to the conducting tube, 

 by means of T-tubes, as shown in Fig. 7 F. Before closing the 

 stop-cocks, we took care that the spring gas, by passing slowly 

 through the tubes for a time, had assumed the pressure and 

 temperature of the surrounding air. 



On closing the collecting bottles, we observed the temperature of the air in 



Fig. 8. 



