56 GREENLAND VOYAGE. 
This process would enable the navigator to re¬ 
store 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 sus¬ 
pended by a thread, to guide them in their 
course through their perilous navigation. 
Being desirous of applying the process to the 
construction of powerful artificial magnets, I pre¬ 
pared (with the assistance 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. 
I he bars for the compound magnet, seven in num¬ 
ber, 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 
