286 ME. G. B. AIET ON THE DIFEEEENCE IN THE MAGNETIC PEOPEETTES 
From this time the bearing is on wood, and the blows are given with a wooden 
mallet, unless otherwise mentioned. 
Exp. 12. Lightly struck, tendency 0 — 60 45 
13. Fairly struck, tendency — —414 35 
14. Very lightly struck, tendency + , . . . +121 5 
15. Fairly struck, tendency — , rested one day — 482 55 
16. After thirty days’ rest, tendency 0 — 386 25 
17. Struck very lightly, tendency 0 — 295 20 
18. Struck fairly, tendency 0 — 19 25 
19. Struck heavily with geological hammer, tendency + , . . . +513 5 
20. (Immediately), first struck heavily, tendency — ; then struck 
heavily (immediately), tendency + +527 55 
21. After one day’s rest, tendency — , and four days’ rest, tendency 0 +438 0 
It appears that the greatest amount of magnetism is about +530°, and this requires 
a heavy blow ; but it is nearly or quite indifierent whether the bars are supported on 
stone or on wood, and whether the blow is given by an iron hammer or a wooden mallet. 
This amount of magnetism, the bars lying with tendency 0, is diminished in one or two 
days by about one-fifth part, and is scarcely diminished further in thirty days. The loss 
of magnetism is not greater when the bars, instead of lying with tendency 0, are placed 
in a tendency opposite to the magnetism with which they are charged. When the 
charge of magnetism is smaller than the maximum, the diminution in a day or two is 
nearly in the same proportion. 
It appears also that the efiect of violence on the bars while lying with tendency 0 is 
not completely to destroy the magnetism ; and that sometimes the magnetism is actually 
increased by the violence. 
II. Proportions of the Aggregate of Magnetism carried by the different classes of Bars ; 
excluding those experiments in which the Bars had been struck while lying vdth 
tendency 0. 
Hot-rolled 
longitudinal. 
Hot-rolled 
transversal. 
Cold-rolled 
longitudinal. 
Cold-rolled 
transversal. 
Experiment 4, tendency 
— 
•226 
•225 
•297 
•250 
5, 
— 
•222 
•209 
•298 
•272 
6, 
— 
•204 
•203 
•306 
•289 
7, 
+ 
•245 
•258 
•263 
•235 
8, 
+ 
•251 
•238 
•266 
•245 
9, 
+ 
•225 
•239 
•269 
•267 
10, 
+ 
•221 
•244 
•231 
•306 
13, 
— 
•241 
•211 
•306 
•244 
14, 
+ 
•349 
•295 
•247 
•107 
15, 
— 
•223 
•222 
•299 
•255 
16, 
— 
•221 
•211 
•303 
•266 
17, 
— 
•201 
•218 
•293 
•288 
19, 
+ 
•209 
•208 
•279 
•305 
20, 
+ 
•207 
•205 
•287 
•302 
21, 
+ 
•196 
•202 
•277 
•323 
Mean 
•229 
•226 
•281 
•264 
