92 
MEASUREMENT OF HIGH TEMPERATURES. 
[bull. 54. 
of cold hydrogen is not unobjectionable, and it is probable that by using 
closed forms H 2 may be dispensed with. I was fortunate, therefore, in 
obtaining crucibles of tire- clay from Messrs. Hall & Son, made in such 
a way that both crucible and central tube are one single piece. A 
crucible of this kind is shown in place in Fig. 14, in which the parts 
have been numbered similarly to Fig. 13. A conical shape is here given 
z*>////////m//77frm, 
m/////////M77////// //////A 
Fig. 14. Perfected form of boiling-point crucible. Scale, |. 
to the crucible, with the object of decreasing the essential charge oil 
zinc and of thereby expediting the boiling. The furnace-body jPjPandl 
lid F' F' are both properly bound with iron, as shown at mm) mm, nun. 
and the body rests on a bed-plate of iron, z z, provided with a hoh 
through which the botttom of the crucible a a partly projects. Z m 
is raised on rather tall legs, allowing the operator to manipulate th( 
thermo-elements from below. The crucible projects above the furnace, 
and the lid b b is shouldered. A battery of three or four of these fur 
(746) 
