602 ON IRON AND STEEL AT WELDING TEMPERATURHS. 
Effect of Pressure in a series of Five Experiments on an Iron Bar 4" in 
diameter, enclosed in a Porcelain and Steel Cylinder. 
Ist Experiment.—Fig. 3 at a temperature of 1347° C. gave a rise of 27° C. 
2nd i —Fig. 4 % ik 1371: 5, . 8° C. 
Fig. 44 is a diagram produced at the same time as fig. 2, but from 
a more sensitive galvanometer. The same scale of tempera- 
ture is not applicable. 
In each experiment pressure applied at time marked P. 
Fig. 5.—3rd Experiment at 1420° C. pressure gave a fall of 27° C. 
Fig. 6.—4th i at 1400° C. i As 5 a Oe 
Fig. 7.—5th 3 at 1300°'C. ms se 5 19° C. 
In each experiment pressure applied at time marked P between first two signals, 
and relieved between last two signals. The current was cut off immediately 
aiter the fourth signal. ; 
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