m 
MEASUREMENT OF HIGH TEMPERATURES. 
Fig. 6 shows a vertical section through the axis of the crucible at 
right angles to that shown in Fig. 5. The lettering in each case is the 
same. U and Fare the supporting arch between the two fires, and T T 
are flues to carry off the products of combustion. E H is the top of 
the furnace, & 8 are supporting columns, W is the entrance of the 
"blast, and P the wind-box opening into the fires by Q Q, shown on Fig. 5. 
Fig. 6. Boiling-point furnace for zinc ; later form ; cross section. Scale, -^. 
The fuel used in this furnace was anthracite coal with a blast furnished 
by a 20-inch fan-blower, the ash-box door being of course closed during 
operation. The flames from the fire rising through the space E E im- 
pinged upon the crucible and passed thence off by the flues T T. In 
practice it was found that by applying fresh fuel in small quantities 
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