1910 - 11 .] Young’s Modulus under an Electric Current. 
241 
Platinum. 
The results for platinum are shown in fig. 21. These curves have 
marked differences from the others ; there is a smaller rate of increase as 
the current rises, and, after the maximum has been attained, the rate of 
decrease is more rapid than the rate of increase. With diminishing current 
there is at first a fall, then a rapid increase to a maximum, and, finally, a 
diminution at about the same rate. The peculiarity platinum exhibits in 
the rapid rise with diminishing current is found to be greatly influenced by 
increase of load, so that it would appear as if the molecular arrangements, 
which give the wire its power to resist extension, were not formed when 
the load was increased. 
The curves obtained from the experiments with constant field and 
varying load are shown in figs. 22 and 23. They show the same character- 
istic rise and fall, but not to the same degree as in the other method of 
experiment. 
Platinum. 
Length = 
Area of cross-section = 
Elongation weight = 
Total load on wire = 
Load per sq. mm. = 
62T2 cms. 
0 0007548 sq. cm. 
500 grams. 
12 kilos. 
15*9 kilos. 
Table Y. 
No. 
Temp. 
Elongation for 
500 grams. 
No. of 
Observations. 
M. 
1 
21 °9 C. 
*03185 cm. 
8 
12-68 x 10 11 
2 
29-2 
*03142 
8 
12-85 
3 
40-6 
*03090 
8 
13-07 
4 
51-3 
*03034 
9 
1331 
5 
650 
•02974 
8 
13-59 
6 
82T 
*02871 
8 
14-08 
7 
97-8 
*02755 
8 
14-67 
8 
104*5 
*02711 
7 
14*91 
9 
113*3 
02716 
6 
14-88 
10 
120*7 
*02763 
8 
14-63 
11 
131*4 
*02871 
8 
14-06 
12 
145*0 
*03034 
10 
13*31 
13 
157*3 
*03185 
9 
12*68 
14 
148*1 
•03257 
9 
12-41 
15 
137*4 
•03234 
8 
12-50 
YOL. XXXI. 
16 
