Effect of Magnetism on Time-pieces. 373 
accurate performance was indispensible, as in time-pieces 
for astronomical and nautical purposes. Though I have 
frequently examined, with great care, watches that did 
not perform well, even when no defect in their construc- 
tion or finishing was apparent, and suspected the balance 
to be magnetic, yet I never could have imagined that this 
influence, operating as a cause, could produce so great an 
effeet as I found upon actual experiment ; for I did not 
expect to find that a balance, even when magnetic, should 
have distinct poles. Happening to have a watch in my 
possession, of excellent workmanship, but which per- 
formed the most irregularly of any watch 1 had ever 
seen, and having repeatedly examined every part with 
particular attention, without being able to discover any 
cause likely to produce such an effect, it put me upon 
examining whether the balance might not be magnetic 
enough to produce the irregularity observed in its rate of 
going. 
I took the balance out of its situation in the watch, 
and, after removing the pendulum spring, put it into a 
poising tool, intending to approach it with a magnet, but 
at a considerable distance, to observe the effeet, while at 
the same time the distance of the magnet should pre- 
clude the possibility of the magnetic virtue being thereby 
communicated to the balance. I had no sooner put it in- 
to the tool than I observed it much out of poise ; that is, 
the one side appeared to be heavier than the other : but, 
as it had been before examined, in that particular, by a 
very careful workman, more than once, I was at a loss to 
determine what to think of the effect I saw ; when hap* 
pening to change the position of the tool upon the board, 
the balance then appeared to be in poise. As there could 
be no magic in the case, it appeared that the balance had 
magnetic polarity, as no other cause could produce the 
effect I had witnessed, and which was repeated as often. 
