296 Proceedings of Eoyal Society of Edinburgh. [sess. 
values obtained with the iron tubes under similar conditions (see 
voL xix. p. 251). 
The following table shows the more striking features of the 
volume changes of the three nickel tubes in various fields. Under 
each heading of field is a column containing the corresponding 
cubical dilatations for the three tubes. The volume changes can be 
easily calculated by multiplying the dilatations by the volumes of 
bore, which are given in the second column : — 
Table of Cubical Dilatations x lOh 
'rul)e. 
Volume 
c.c. 
10 
15 
1 
35 
Field. 
62 1 102 
150 
200 
400 
1 600 
I. 
224-47 
-0-5 
0 
+ 0-8 
0 
-9 
-24 
-47 
-67 
- 98 
-110 
II. 
87-58 
... 
-0-7 
0 
+ 1 
0 
-10 
-35 
-53 
- 79 
- 87 
III. 
17-88 
+ 1-0 
+ 2-5 
+ 9 
0 
-36 
-84 
-207 
-236 
In the following table a direct comparison is made between the 
dilatations and the average intensities of magnetisation in the metal 
of the tubes. For in all probability it is the magnetisation rather 
than the magnetising force that is essentially involved. _ The 
magnetisations were obtained directly from the experiments de- 
scribed in the preceding Note on the Magnetic Induction in Nickel 
Tubes (p. 277) : — 
Cubical Dilatations x lOh 
Tube. 
50 1 
80 1 
' 150 1 
Intensity of Magnetisation. 
230 1 300 1 340 | 410 
1 500 
600 
1 700 
I. 
- -3 
0 
+ 0-8 
0 
-3-5 
-7 
-14 
-27 
- 55 
-110 
II. 
- -7 
0 
+ 1 
+ 1 
0 
- 4-5 
-19 
- 48 
- 87 
III. 
+ 2 
+ 7-5 
+ 9 
+ 7-5 
0 
-32 
-125 
-236 
From these tables certain broad conclusions may at once be 
drawn. 
