632 Dr. E. P. Harrison on the Temperature- Variation 
curve is regular ; between 365° and 380° there occurs an 
anomalous change i in the expansion, while above 380° the curve 
is again regular, though now it is linear with a different slope 
to the regular part of the curve which precedes it. 
i Fics. 
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100 200 300 370 400 500 ——_EMPERATURE ——~ 
No difference in the position or shape of the anomalous 
portion of this curve was noticed, whether the temperature 
was rising or falling. It is also worthy of notice that in every 
case the wire returned after heating to its original length: 
there was no permanent elongation. 
Fig. 4. 
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100 200 Son onn 500 <—T — 
From the curve fig. 3 is calculated the mean coefficient 
of expansion over 50° ranges, between 0° and 300°, and the 
result is shown graphically in fig. 4 
