1906-7.] Variation of Young's Modulus under Electric Current. 353 
this case, the rate of increase was slower than with the others, and the 
maximum not reached until the temperature had risen to 110°. Beyond 
this the modulus fell till the temperature rose to 155°, the rate of fall being 
greater than that of rise. 
Platinum Wire. 
Length = 62T0 cms. 
Area of cross-section = ’0007548 sq. cms. 
Stretching weight = 200 grams. 
No. 
Temp. 
Elongation for 
200 grams. 
No. of 
Observations. 
M. 
1 
20°-0 C. 
•01302 cm. 
8 
12-40 x 10 11 
2 
22 -9 
•01280 
8 
12-62 
3 
29 *7 
•01266 
10 
12-75 
4 
46 -9 
•01215 
9 
13-30 
5 
61 -5 
*01189' 
10 
13-58 
6 
66 -5 
•01157 
8 
13-95 
7 
81 -6 
•01136 
12 
14-21 
8 
93 -1 
•01101 
8 
14-67 
9 
101 -8 
•01066 
8 
15T5 
10 
107 ’6 
•01049 
8 
15-40 
11 
113 3 
•01055 
10 
15-31 
12 
124 *9 
•01087 
6 
14-85 
13 
139 ’7 
•01159 
8 
13-93 
14 
155 -0 
•01276 
8 
12-65 
15 
150 -3 
•01298 
9 
12-44 
16 
143 2 
•01295 
10 
12*47 
17 
128 -0 
•01273 
11 
12-68 
18 
116 -1 
•01213 
10 
13-31 
19 
110 ’4 
•01149 
12 
14-06 
20 
107 -0 
•01131 
8 
14-28 
21 
104 -5 
•01078 
8 
14-97 
22 
100 -6 
•01037 
8 
15-57 
23 
96 *5 
•009539 
6 
16-45 
24 
89 *4 
•009308 
7 
17-35 
25 
85 -3 
•009144 
8 
17-60 
26 
82 -5 
•009228 
8 
17-50 
27 
77 -0 
•009800 
8 
16-48 
28 
71 ’8 
•01030 
7 
15-68 
29 
60 -7 
•01087 
8 
14-85 
30 
50 -5 
•01132 
10 
14-27 
31 
40 T 
•01167 
8 
13-83 
32 
29 *4 
•01193 
12 
13-54 
33 
20 ’6 
•01111 
8 
14-53 
Vertical Wire. 
34 
1 1 
20 -2 
•01314 
7 
12-29 
The current was then diminished, and this caused a further decrease in 
the modulus, the minimum being about 148°. Below this, there was a 
rapid rise in the modulus, and the two curves cut one another at 103°. It 
vol. xxvn. 23 
