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Proceedings of the Koyal Society of Edinburgh. [Sess. 
of b, no change was obtained in the constants, although the period of 
oscillation after fatigue was found to have increased slightly. The average 
values gave : 
Before fatigue, period of 10 oscillations = 178 secs. 
After ,, „ „ =182‘5 secs. 
Effects of Quenching. 
A rather interesting result was obtained when copper * was raised to a 
bright red heat and cooled suddenly. The subsequent testing showed that 
three lines were necessary to cover all the points over the usual range, 
the values in the first experiment being : 
A. a = 0 B. a= 50 C. a = 50 
n = 2‘45 n = *30 n = '50. 
* Cut from the same wire as was formerly tested. 
