EFFECT OF TEMPERATURE ON COPPER. 285 
ture differ from those actually measured at the ordinary tempera- 
ture. Taking the extreme case, in which the increase of tem- 
perature is 500° F., and assuming the linear coefficient of expan- 
sion, per degree Fahrenheit, of copper to be 0000095 or -00475 
per 500°, the following statement shows the error involved in the 
particular case of compression pieces 13 — 25, and will serve as an 
illustration for the whole series. 
Length ins. Diam. ins. Area sq. ins. 
Original 5-000 1-375 1°485 
Final 5-024 : 1381 hh OS 
This error being negligible for the purpose in hand, and being 
the greatest that can occur, will not be further referred to in the 
following enquiry. 
4. Temperature and ultimate tensile strength.—The variation of 
the ultimate tensile strength with temperature is shown in the 
following table, and the results are plotted in Fig. 3. 
Table I. 
oe of} Temp. of | Diameter| Ajea | Breaking | Breaking Stress | 
‘est. | bath F.° | Inches. | Sq, Inches, | —total lbs Ibs. per sq. in. 
4L 25 ‘750 | -4418 13,850 31,350 
11 | 208 750 | +4418 12,100 7 390 
33 | 244 °750 | °4418 11,750 26,600 
34 | 348 750 | 4418 0.900 24,670 
8 | 57 | -748| -4396 | 13,800 | 30,260 
81 57 | -750| -4418 | 18,874 31,410 
7| 38 | -750| -4418 | 14,075 |. 31,860 
6 | 102 | -750| -4418 | 13,400 — 30,330 
| 5 | 208 | -760| 4418 | 12,300 27,840 
| 4 | 351 | -751 | -4431 10.450 23.580 
