ERRORS OF CHRONOMETERS. 
7 
The peasantry and fishermen inhabiting the 
borders of Loch Ryan are an inoffensive and un¬ 
obtrusive people. Unless they are invited, they 
seldom board the ships lying at The Kern, and 
are rarely either craving or troublesome when 
they are required to traffic. Their chief oc¬ 
cupations are fishing, dredging for oysters, and 
a little agricultural labour. Numbers of boats 
were seen daily employed in the oyster-fishery. 
The oysters they take, which are generally of a 
small kind, are sold for 8d. a hundred. 
During the leisure afforded by our detention 
at Loch Ryan, I employed myself in construct¬ 
ing a temporary apparatus for obviating the er¬ 
rors produced in the rate of chronometers, by the 
action of terrestrial magnetism on those parts of 
the instalments which are formed of steel. This 
action on chronometers, whose balances have acci¬ 
dentally acquired magnetic properties (and there 
are scarcely any that are not more or less magne¬ 
tic), is considerable, and is probably the principal 
cause of the difference of the land and sea rates 
of these instruments. The general mode in which 
this disturbing cause acts, is sufficiently obvious. 
With regard to a magnetic balance, it is evident, 
that when the chronometer is in such a position 
that its north pole is directed towards the north 
of the globe, its rate will be accelerated,—when 
