618 



Scientific Proceedings, Royal Dublin Society. 



(b) Modified form of Experimental Tule used. 



Owing to the difficulty in obtaining apparatus, it was decided to make 

 the required modification of the experimental tube in the laboratory. It 

 was designed and made as shown in the diagram (fig. 5). At the upper end 

 of the tube there is a hollow stopper A ground in, which controls the con- 

 nexion to the manometer D and the gas reservoir C. This stopper also has 

 a stopcock F. fused on to it at the top to permit of the tube being filled with 



Fig. 4. Fig. 5. 



water when used in conjunction with another stopcock B, fused on to the 

 lower end of the tube. The manometer D and the gas reservoir C are 

 fused on to the tube in such positions that the openings correspond with the 

 holes in the stopper. The whole apparatus is provided with a water-jacket 

 as shown, through the bottom of which the ends of the gas reservoir and the 

 manometer project, in order to allow them to be connected by rubber tubing 

 with the mercury reservoir E and the tube G, respectively. 



