88 ‘Mr, McClung on the Effect of Temperature on the 
remain air-tight at the higher temperatures. There must of 
necessity be in the vessel some joints between different 
materials, and the problem of how to make these joints air- 
tight presented considerable difficulty. Several methods of 
making the vessel air-tight were tried, none of which proved 
satisfactory until the following apparatus was evolved, which 
is shown in detail in fig. 3. 

oe 
a 
~ 
mi OE 
5 Pp AX 
A HR 
> O25 
vA 
~ 
AB wasa circular brass cylinder 24 ems. long and 7°6 ems. 
in diameter. The end A was Joined on to the cylinder by 
brazing. All the brass joints were made by brazing wherever 
