364 Mr. Barlow on the effects produced in the rates of 
plain unmagnetized iron ; for notwithstanding, according to 
the present received doctrine of magnetism, every mass of 
soft iron becomes a temporary magnet by induction from the 
earth ; yet I am not aware that ever any particular action has 
been discovered between two pieces of iron, whether hard or 
soft, which had not previously acquired a polar quality ; the 
largest mass of iron, for instance, will not, that I am aware 
of, attract and give direction to the lightest and most freely 
suspended needle of soft iron, or of unmagnetized steel. 
Now, if this be admitted, it necessarily follows, that plain 
unmagnetized iron can only be supposed to act on the balance 
of a chronometer, when that balance has acquired a polar or 
directive quality; and then, as I have already stated, it will 
have a tendency to produce an acceleration, or retardation, 
according to its position with respect to the balance, and the 
previous adjustment of the machine. 
If this be actually the case, it may probably appear sin- 
gular, that all Mr. Fisher’s chronometers were accelerated ; 
but it is not much less so, that five out of the six which I 
used in my experiments were as decidedly retarded. It will 
likewise, after examining my experiments, be difficult to ac- 
count for that high degree of acceleration noticed by Mr. 
Fisher ; for it will be seen that, although I approximated 
some of my chronometers to within two or three inches of 
the surface of an iron ball thirteen inches in diameter, the 
utmost effect which I could produce did not exceed 4" per 
day ; whereas Mr. Fisher makes his amount to 8" or 9" per 
day ; and yet we can scarcely imagine that he brought his 
chronometers so closely within the immediate sphere of action 
of any mass of iron, more powerful than that described in 
