ON THE MAGNETISATION OF COBALT. 
349 
Table 11. 
%'■ 
First 
“ on.” 
Cyclic 
“on”-“ off.” 
v/% 
Shock-effect 
Cyclic “ on ” — “off ” 
Sf 
1T5 N (1-2) 
3-40 
2-17 
- -62 
+ 
•46 
•48 
- •32 
•21 
1-44 N (16) 
2-62 
1-23 
-62 
+ 
•51 
•37 
•43 
•41 
I-6I S (14) 
4-32 
N 
4-32 
, , 
•74 
1-0 
, , 
1-9 N (II) 
5-9 
3-4 
1-1 
+ 
•42 
•50 
•26 
•124 
4'3 N (10) 
8-6 
4-9 
2-0 
4- 
•49 
■33 
•29 
■100 
7-8 N (9) 
13-1 
6-9 
3-7 
+ 
■54 
•28 
•32 
•078 
9-9 N (8) 
16-4 
9-0 
4-6 
+ 
■62 
•26 
-.32 
•069 
18-4 N (2) 
27-9 
15-7 
8-6 
+ 
■26 
•23 
•32 
•017 
19-2 S (I) 
29-9 
19-0 
5-4 
+ 
•15 
•23 
•19 
■008 
25'6 S (.3) 
39-4 
25-3 
9-5 
-i- 
•15 
•24 
•25 
•006 
36-8 S (4) 
51-0 
34-6 
12-9 
— 
•22 
•22 
•25 
- -006 
66-9 S (5) 
66-1 
40-4 
17-2 
— 
1-07 
•18 
•24 
- -027 
100-7 N (6) 
68-5 
45-6 
16-9 
— 
1-20 
•14 
•23 
- -026 
126-6 N (7) 
70-9 
48-6 
17-8 
—! 
1-38 
•13 
•23 
- -028 
§ 25. In Table L is the strength of the field calculated as is explained in § 19, 
3i is the intensity and the coefficient of induced magnetisation in the rod previous 
to the application of any pressures ; while 3*3 is the intensity and the coefficient of 
induced magnetisation in the rod free from pressure after all the pressures cycles have 
been applied. Thus — 3i is the increase in the magnetisation taking place during 
the application of the pressure cycles. Tlielr application occupied a considerable time, 
during which absolute steadiness in the current could hardly be expected; and so 
3^ — 3i is probably in no case an absolutely exact measure of the increase in the 
magnetisation due to the pressure cycles. By first “ on ” is meant the increase in the 
magnetisation caused by the first application of pressure. Cyclic “ on ” — “ off'" gives 
the average algebraic excess of the magnetisation existing when pressure is “on” 
over that existing when pressure is “ off.” As ali-eady explained the shock-effect is 
the algebraic excess of the first “ on ” over the cyclic “ on ” — “ ojf.” 
The second last column gives the ratio of the shock-effect to the intensity of the 
magnetisation prior to pressure, while the last column gives the ratio of the cyclic 
“on” — “ off” to the intensity of magnetisation in the cyclic state. Thus the figures 
in these two columns may fairly be regarded as measuring the importance in the 
different fields of the shock-effect and the cyclic effect resj^ectively. 
In the weakest field the last tliree columns have no entries, because the experiments 
determining the cyclic effect of pressure failed to indicate a clear result. 
The entries in the two last fields indicate, as they do elsewhere, that no obser¬ 
vations of the corresponding quantities were obtained. In these fields when the 
compensating coil exactly balanced the coil current so that in the absence of the rod 
the spot was at the centre of the scale, the introduction of the rod drove the spot off 
the scale. The compensating coil was thus moved so as to neutralise part of the effect 
