PROPERTIES OF IRON AT A HIGH TEMPERATURE. 
451 
The following experiment is instructive, as showing a phenomenon which constantly 
recurs, namely, that after not quite perfect demagnetisation, as above described, the 
first kick of the galvanometer being in the same direction as the last magnetising 
force, the first kick is very materially greater than the reverse kick for small magnet¬ 
ising forces, is somewhat less for medium forces, and about the same for great forces. 
I have no explanation of this to offer. 
The ring was heated until the resistance of the secondary coil was about 2'4, 
corresponding to a temperature of 529° C. Currents successively diminishing in 
amount were then passed through the primary, each current being reversed ten times. 
The last currents gave magnetising forces 1‘2, 0‘6, 0*3, 0T5, 0'075, and 0‘05, the 
intention being to demagnetise the sample. The ring was allowed to cool till the 
resistance of secondary was 2'0, corresponding to a temperature of 398° C. The 
following series of observations was made ; the first kick was in all cases produced by 
a reversal of current from the direction of the last demao-netising current; the second 
kick by a reversal in the opposite sense. 
Table 14. 
Magnetising: 
Galvanometer 
Eesistance in 
force. 
kick. 
circuit. 
0-075 
i 
20-51 
L 13-5 J 
12-43 
0-15 
41-51 
32-5 J 
? > 
0-3 
r 104-0 
81-0 
5) 
0-6 
r 284-51 
L 241-0 J 
1-2 
143-5 1 
L150-0 J 
102-43 
2-1 
i 
r 262-5 1 
L 265-0 J 
^ 5 
' 4-0 
i 
r 351-01 
L 351-0 J 
5? 
7-3 
1210-01 
211-5 
202-43 
12-1 
1 235-51 
234-0 
5 ? 
43-4 
272-5 1 
L 271-5 J 
9? 
The resistance of the secondary coil at the end of the experiment was 2‘05 ; 
temperature, 415° C. 
The sample was again heated until it became non-magnetic, and then allow^ed to 
cool very slowly, and the following series of observations w^ere made, the ring being- 
demagnetised as before after each series. The actual kicks of the galvanometer are 
3 M 2 
