214 Mr. Scoresby's experiments and observations on the 
large employed, there would be no limit to the attractive force 
developed in the steel wires, until they were magnetised to 
saturation. The quantity of effect produced by an iron bar 
seems to be in some certain proportion to the amount of its 
own magnetic energy, as indicated by its action on a compass 
needle, but not in the proportion of its lifting power. 
5. It is a well known fact in magnetics, that the capacity 
of steel for magnetism is increased by time — by repeated re- 
newals of the magnetising process at intervals — and by keep- 
ing the magnet under constraint, either by the contact of 
other magnetic substances, or by the use of conductors be- 
tween the opposite poles. Hence I expected, that a wire 
magnetised by percussion to a maximum for the time, might 
have its power subsequently increased, day after day, in con- 
sequence of its capacity being increased by a repetition of the 
process. To a certain extent this was the case ; but when 
the iron bars had acquired their maximum energy, and the 
wires were then hammered until there was a decided sus- 
pension of increase of energy, no future repetition of the 
process, however laboriously conducted, gave me any ad- 
ditional power. [Experiments No. IV. and XV.] 
On the first view of the subject, I was at a loss to account 
for the suspension of the augmentation, when I had calculated 
on an increased capacity for magnetic energy, with the con- 
tinuation of the process, agreeable to the known laws of mag- 
netics ; but I eventually perceived that the analogy, with the 
ordinary communication of magnetism, was not complete. It 
was evident that the suspension of augmentation did not arise 
from the want of capacity in the steel for magnetism, the wires 
not being near a state of saturation ; but it arose from the 
