34S 
Mil. C. CHIIEE ON THE EFFECTS OE PRESSURE 
then adjusted to give the field desired. When tlie ammeter and the scale reading 
became steady, the rod was brought up and pushed rapidly into the coil, and the pin 
secured. The difference between the scale readings when stationary, before and after 
the introduction of the rod, supplied the data for calculating the initial value of the 
induced magnetisation. 
A considerable number of cycles of pressure “on” and “off” were then performed, 
the scale readiiig, when become stationary, being usually taken after each “on” and 
“ off” Sometimes when readings had been taken of the effects of the first four or 
five pressure cycles, some five or six cycles were applied in rapid succession and then 
the taking of readings once more resumed. When a sufficient number of readings 
had been taken for the calcidation of the average efiect of a pressure cycle, the circuit 
was suddenly broken, the rod being always free from pressure during the break. 
When the scale reading had become stationary after the break and had been 
observed, some six pressure cycles were applied, readings being taken after each “on” 
and “off” A series of six pressure cycles were then applied whose effects were not 
observed. These were followed by some six or seven more [iressure cycles whose effects 
were observed. Finally the rod was removed to a distance and the magnetometer 
zero taken. The difference between the scale reading taken immediately after the 
break of the current and that taken after the removal of the rod supplied the data 
for calculating the initial value of the residual magnetisation. 
Table 1. 
3 i - 
n- 
A — 3 i - 
h -' o . 
First 
“ on.” 
Cyclic 
“on ” — “ off.” 
Shock-eft’ect 
Cyclic “on’’—“off” 
3 . 
•80 S (13) 
1'.54 
1-9 
1-08 
3-3 
•77 
1-15 N (12) 
4-01 
3-5 
3-09 
6-2 
3-09 
•b 
•57 
•ii 
1-41 N (15) 
4-63 
3-2 
2-47 
4-9 
2-93 
•65 
•49 
•09 
1-61 S (14) 
3-55 
2-2 
2-32 
3-6 
1-39 
•11 
•36 
•02 
1-9 N(1L) 
8-9 
4-7 
2-8 
6-2 
3-7 
1-2 
•27 
•10 
4-3 N (10) 
19-6 
4-5 
6-9 
6-1 
7-4 
1-6 
•30 
-059 
7-8 N (9) 
38-0 
4-8 
9-7 
6-1 
10-0 
2-8 
•19 
•059 
9-9 N (8) 
50-0 
5-0 
13-1 
6-4 
13-9 
3-0 
•21 
•048 
18-4 N (2) 
107-5 
5-8 
15-7 
6-7 
19-1 
5-0 
•13 
•041 
19-2 S (1) 
113-7 
5-9 
13-9 
6-6 
16-7 
4-8 
•11 
•037 
25-6 S (3) 
148-5 
5-8 
16-8 
6-5 
24-4 
5-8 
•12 
•035 
36-8 S (4) 
218-1 
5-9 
15-2 
6-3 
20-6 
7-2 
•06 
.031 
66-9 S (5) 
368-8 
5-5 
10-6 
5-7 
15-0 
4-4 
•029 
•012 
lOU-7 N (6) 
8-4 
1-4 
•015* 
•003* 
126-6 N (7) 
4-0 
- 0-7 
•009* 
- - 001 * 
* The values employed here for and 3.i are derived from subsequent table.s. 
