288 W. H. WARREN AND S. H. BARRACLOUGH. 
Tt is evident from these figures that besides temperature, there ~ 
are other, and probably uncontrollable, conditions which affect 
the elongation. Although the curves (Figs. 4 and 5) of total and 
400. 200 -300': 400 “500 600 
Figs. 4 and 5. 
Abscisse Temperatures Fahr 
Ordinates Fig. 4, Total Elongation %. 
Ordinates Fig. 5, General Elongation %. 
general elongation are consequently but ill-defined in position, 
they yet indicate the probable presence of a maximum elongation 
at a temperature of approximately 200° F. It would not seem 
possible however to specify any particular percentage of elongation 
which a test specimen of copper should comply with. 
6. Temperature and contraction of area.—The contraction of 
area as measured on test pieces, Nos. 1 —11, varied from 37 to 
63 per cent., but the method of variation with temperature was 
exceedingly irregular, it being impossible to deduce any simple 
relationship between the two quantities. As in the case of the 
percentage elongation, the results when plotted appeared to 
indicate the presence of a maximum contraction of area at 4 
temperature of 200° to 250°, but the conclusion could not be relied 
upon with any degree of certainty, and for that reason the curves 
are not reproduced, 
