I . RESEARCH. 



495 



tubes. When the paraffin is solidified, the tubes are united by a joint, 

 -vrhich is perfectly air-tight, -which will resist very considerable pressure, and 

 which is quite unaffected by the passage of the ozone. This simple joint is 

 an essential feature of this arrangement, and will doubtless be of great 

 service in many forms of gas apparatus. 



The gas-holder consists of a glass bell p, contained in a glass cylinder q, 

 in which it is suspended, being supported by a knob of glass passing through 

 a cap fitted to the top of the jar. This cap is made in two pieces, which are 

 subsequently united so as to be readily placed in a proper position as a 

 support to the glass bell. 



F/G. e 



