352 
MB. C. CHREE ON THE EFFECTS OF PRESSURE 
Table III. 
3i. 
U- 
Sa - 3i- 
I irst 
“ on.” 
Cyclic 
Shock-effect 
Cyclic “on” — “off ” 
3i 
32 
84-8 
409 
4-8 
7-4 
+ 9-2 
+ 2-2 
+ -017 
E ‘005 
106-4 
472 
4-4 
4-6 
•E 5-0 
+ 0-7 
E -009 
E -001 
126-G 
526 
4-1 
155 m 
554 
.3-6 
2-3 
- 1-2 
- 2-1 
E -002 
- -004 
181 
582 
3-2 
- 1-8 
- 2-4 
E -001 
— -004 
210 
611 
2-9 
.T1 
- 3-2 
— -005 
270 m 
629 
2-3 
1-3 
- 2-4 
- .3-6 
E -002 
— -006 
282 
624 
2-2 
293 
613 
2-1 
1-1 
- 2-4 
- 2-9 
o 
p 
E 
- -005 
.339 
654 
1-9 
.. 
357 
669 
1-9 
- 4-5 
- 3-2 
- -002 
— -005 
406 TO 
690 
1-7 
7-9 
- 2-8 
-3-8 
^ -001 
— -005 
541 
707 
1-3 
17-0 
- 1-5 
- 2-3 
E -001 
- -003 
633 
777 
1-2 
34 
- 5-2 
- 3-4 
- -002 
- -004 
r 90-Q 1 
725 
791 
1-1 
{tU 
2*2 
• • 
- 003 
1 
Table IV. 
Nnmber of 
fields. 
Limiting fields. 
Average 
first “ on.” 
Average 
cyclic “ on ”-“ off.” 
Average 
shock-effect -e 3/. 
7 
8.5-210 
- 16-4 
- 1-14 
- -21 
8 
250-355 
17-4 
1-09 
•21 
4 
400-725 
14-6 
•SO 
•19 
§ 30. In Table III., which gives the observations on the induced magnetism, the 
headings have the same meanings as in Table I. When m is attached to the strength 
of the field, two or three separate experiments were conducted with fields of approxi¬ 
mately this strength, and the results given in the table are the averages of those 
obtained. The blanks are mainly due to unsteadiness in the scale-readings brought 
about by fluctuations in the strength of the magnetising current. 
In no case probably, as already explained, does the column headed —3] g'i''® 
with perfect accuracy the change in the magnetisation produced by the pressure cycles 
alone, and in fields over 400 units the changes under this head must mainly be due to 
a totally different cause, viz., the heating of the rod. In these high fields the scale¬ 
reading did not remain stationary in the absence of pressure, but showed a progressive 
increase of magnetisation. To obtain the cyclic effect, the pressures were applied and 
removed at as nearly uniform intervals as possible, and the changes in the magnetisa¬ 
tion occurring in successive intervals were compared. 
In the strongest field, after the application of a large number of pressure cycles. 
