60 
MEASUREMENT OF HIGH TEMPERATURES 
below to a wide flange in the neck fr, secure the tube by screw pressure 
between the head m and the flange of h It is often convenient to use 
gaskets of asbestos or any other kind of packing at the upper and lower 
end of the tube. The head m, moreover, is in communication with the 
condenser by means of the lateral tube of gas pipe, m n o g. Hence the 
vapor arising from the surface of boiling liquid, a a, can escape either 
Pig. 2. Apparatus for constant temperature between 100° and 300°. Scale, T V 
above or below, and the respective circulations are regulated by a 
faucet,/. We found, however, that in case of corrosive or hot liquid, / 
soon begins to leak, and that it is advantageous to partially stop up the 
lower passage by a ball suspended in the cone d d from a platinum 
wire passing through Jc m I. In this way the use of the cock / may be 
avoided. 
To heat the sphere A A A we used a large ring burner, B B, about 
22 cm in diameter and provided on its inner surface with 130 jet boles, 
0.15 cm each in diameter. This ring burner was so made that it could 
be used either with or without blast, according as temperatures relatively 
low or high were to be obtained. Its position is adjustable at pleasure 
by a clamp attached to the standard G C. Another clamp attached to 
the standard D D acts as a safeguard against lateral vibrations of the 
sphere AAA, the main weight of which is supported by the exit pipe 
d ef to the upper end of which it is screwed. A final clamp and stand- 
ard, E r, facilitates the adjustment of the exit pipe o n m. The sphere 
is provided with a feed pipe, q g, and an appropriate gauge, p p, to 
(714) 
