342 



of these tubes a reaches almost to the bottom, and to it the 

 thermometer is attached. At the upper end it is provided with 

 a simple glass-tap and terminates with a short piece of rubber- 

 tubing. A glass-bulb B, holding about 15 cc. more than the 

 gas-burette of the analysis-apparatus and likewise provided with 

 a tap, can be connected with the tube by means of this rubber- 

 tubing. The other tube h is short and of narrow bore and is 



provided with a three- 

 way-tap. 



In order to take in 

 the air-sample all taps 

 are opened and water by 

 way of a sucked into the 

 bulb B, allowing it to be 

 replaced through the tube 

 b by pure atmospheric 

 D air. Then the taps are 



closed, the bulb discon- 

 nected, the thermometer 

 read, and the bottle vio- 

 lently shaken for one 

 minute or thereabouts. 

 The tap b is thereupon 

 opened for a moment in 

 order to equalize the pres- 

 sure in the bottle with 



Fig. 3. 



that of the atmosphere , and the shaking then repeated for 

 another minute. The temperature of the water should not be 

 allowed to vary more than V4" during the shaking, and the 

 temperature of the bulb too should be kept fairly unaltered. 



When the shaking is finished the bottle is connected with 

 the analysis-apparatus and the bulb B. The manipulations are 

 made in the following order (see fig. 4). 



The gas-burette €■ is filled with mercury. 



