48 Account of Captain Scoresby's 
the navigator to restore sufficient polarity for the guidance of 
his ship, in a few seconds. And, in cases of vessels foundering 
at sea, or being destroyed by fire or lightning, in which the 
crew are compelled to take refuge in the boats at a moment’s 
warning, and without having time to secure a compass, (a case 
which has occurred hundreds of times), the same process might 
enable the distressed voyagers to give polarity to the blade of a 
penknife* or the limb of a pair of scissors, or even to an iron 
nail, which would probably be sufficient, when suspended by a 
thread, to guide them in their course through their perilous na- 
vigation.” 
We have seen Mr Scoresby’s experiment illustrative of the 
practicability of this. He used a small bar of soft steel, with 
a hole drilled two-thirds through it, so as to be capable of turn- 
ing on the point of a needle. One blow with a hammer when 
it was held vertically on a poker, gave it such magnetic energy, 
that it traversed with great celerity. 
“ Being desirous (says he) of applying the process to the con- 
struction of powerful artificial magnets, I prepared (with the as- 
sistance of the armourer on board) six bars of soft steel, and bars 
properly tempered, suitable for a large compound magnet. The 
soft steel bars were nearly eight inches long, half an inch broad, 
and a sixth of an inch thick. The bars for the compound mag- 
net, seven in number, which were of the horse-shoe form, were 
each two feet long before they were curved, and eleven inches 
from the crown to the end, when finished, one inch broad, and 
three-eighths thick. These bars were combined by three pins 
passing through the whole, and screwing into the last ; and any 
number of them could be united into one magnet, by means of 
sophical Transactions, occurred in the year 1748 — 9, on the 9th of January. The 
ship Dover, on its way from New -York to London, was struck by lightning during 
a fierce storm, which was encountered in the latitude of 47° 30' N. and longitude 
22° 15' W. On receiving the shock, the captain, and most of the crew, were for 
a while disabled in their limbs, or by blindness, — the main.mast was almost per- 
forated, — the upper and lower decks and quick work were stove, — the cabins, 
bulk-heads, and one of the main lodging-knees of the beams were started or drove 
down : and, among several other singular circumstances, the magnetism of all the 
compasses (four in number) was destroyed, or the poles inverted. 
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