RESEARCHES IN MAGNETISM. 
565 
to the successive steps by which the magnetising force was increased. Up to this 
point there had been no disturbance. Then the wire was tapped, or rather beaten 
smartly against the table, the magnetising force being kept constant. The magnetisa¬ 
tion was then, after tapping, measured by slipping off the induction coil. Next, the 
induction coil was replaced and the magnetising force again raised by steps, without 
disturbance, to a new value, the magnetisation being determined as before by summa¬ 
tion of throws. Then the wire was again tapped, and the resulting magnetism again 
determined by slipping off the induction coil, and so on. A similar series of observa¬ 
tions were made at various stages during the removal of the magnetising force. The 
results are given below, and graphically in Plate 61, fig. 23, where the full lines show 
the magnetic changes which occurred while the rod was left undisturbed, and the 
broken lines those which were produced by vibration. At the outset the wire had a 
magnetism (S3) of 170, not extractable by tapping. 
Effects of Vibration on the Magnetism of Soft Iron, Plate 61, fig. 23. 
A 
Change of 39, 
SB. 
caused by vibration under 
constant value of Jp. 
r o 
170 
0-32 
O'32 (with vibration) 
1901 
6,620 j 
+ 6430 
1-08 
6,720 
1-61 
1'61 (with vibration) 
7,1201 
11,600 j 
+ 4480 
2-00 
11,620 
2-9 
11,770 
On.. < 
3-4 
3'4 (with vibration) 
11,9401 
12,960 j 
+ 1020 
5-3 
13,100 
6-9 
13,360 
7'8 
7'8 (with vibration) 
13,6601 
14,240 j 
+ 580 
11-2 
14,330 
133 
14,420 
16-5 
14,5601 
+ 80 
16'5 (with vibration) 
14,640 j 
r 
rn-6 
14,600 
8-9 
14,530 
7'2 
7'2 (with vibration) 
14,4701 
13,040 j 
-1430 
5'2 
12,970 
3-1 
12,910 
Off.. < 
1-77 
1'77 (with vibration) 
12,7901 
11,440 j 
-1350 
T16 
11,320 
0-77 
11,290 
0'33 
0'33 (with vibration) 
11,2601 
6,880 j 
-4380 
0-23 
6,880 
0 
6,8801 
s 
-6560 
l 0 (with vibration) 
320 j 
4 D 
MDCCCLXXXV. 
