51 
Magnetical Experiments > fyc. 
As steel does not receive, immediately on being touched, the 
full degree of magnetic energy of which it is susceptible, a con- 
ductor was applied to the magnet now formed ; and it was laid 
aside, with the view of augmenting its power on a subsequent 
occasion.* *” 
The errors produced in the rates of Chronometers, by the 
magnetism of their balances, a subject of great consequence to 
navigators, has occupied a good deal of the attention of Captain 
Scoresby. 
It has long been known that when chronometers are taken to 
sea, a change is generally found to take place in the rate deter- 
mined on shore. 
44 This change of rate,” says Mr Scoresby, 64 that had usually 
been supposed to arise from the motion of the ship, has recently 
been attributed, by Mr Fisher, who accompanied Captain Buchan 
in his' Voyage towards the North Pole in the year 1818, 4 to the 
magnetic action exerted by the iron in the ship upon the inner 
rim of the Chronometer’s balance, which is composed of steel.’ 
I apprehend, however, that it will be very easy to shew, that, al- 
though the alteration of rate may be, and most probably is, ow- 
ing to magnetism, yet the magnetic action of the iron in the ship, 
excepting in cases where chronometers are placed in immediate 
contact with large masses of iron, can contribute but in a very 
small degree to the error in question. For, in the same propor- 
tion as the magnetism of the earth, or the directive force on the 
compass-needle, exceeds the magnetism of the ship, or the de- 
viating force, the influence of terrestial magnetism on the chro- 
nometer, must, I conceive, exceed that influence exerted by the 
iron in the ship on the chronometer. A modified action, indeed, 
takes place where the direction of the magnetic force of the 
earth differs from the direction of the f 6 local attraction” of the 
6 4 ship but yet the combined influences of the two forces, how- 
ever modified by direction, should, I imagine, be similar on the 
balance of the chronometer, which vibrates in a horizontal posi- 
tion, to what it is on the compass-needle, which traverses in the 
same position. 
cient, I apprehend, than that of Canton, one blow with a hammer being capable of 
developing as much magnetism as a quarter of an hour’s labour with a poker and 
tongs.” 
* Journal of a Voyage, to Greenland , p. 56. 13 % 
