384 Mr. Barlow on the effects produced in the rates of 
machine, the most delicate, perhaps, of any in the entire circle 
of the mechanical arts. 
We accordingly went into his work-shop, and having de- 
tached a balance from a chronometer, we suspended it very 
nicely in its frame, and brought it near a piece of iron of 
some magnitude, which happened to be at hand, and an 
action between it and the balance was rendered immediately 
obvious ; and it was of that kind which seemed to imply, that 
it proceeded from the magnetism of the balance, or of the 
spring which remained attached to it ; that is, if the motion 
which we gave to the balance terminated in a certain place, a 
trifling recoil, or repulsion, might be distinguished ; but if 
the opposite side of the balance was nearest to the iron when 
the motion ceased, then, a slight degree of attraction was 
equally distinguishable ; and Mr. Frodsham had no doubt 
that such an action as we then noticed, was amply sufficient 
to change the rate of the chronometer, of which the balance 
formed a part, when brought within the sphere of attraction 
of any such iron mass. 
The above experiment was made with the balance and 
frame placed near the bottom of the piece of iron ; it was 
now repeated near its upper part, and a similar action was 
distinguishable ; but it appertained to the reverse extremi- 
ties of the balance. 
I have said, that these results were such as indicated the 
presence of magnetism in the balance or spring ; and it may 
not be amiss to advert here to this subject a little more par- 
ticularly, and to explain how I imagine we may always dis- 
tinguish between the magnetism of the balance, and that of 
the attracting body. 
