Prof. Hansteen on the Magnetic Poles, 329 
the Venetians, in their commerce on the Red Sea, brought the 
knowledge of it with them from the East. That our Norwegian 
ancestors in this, were not behind the inhabitants of the south, 
naay be seen from the 1 st part of the Landnama Book, chap. 2. 
sect. 7., where it is related that the famous Pirate Floke Vil- 
gerdarson, the third discoverer of Iceland, when, about the year 
860, he went out from Rogaland in Norv/ay, to search for Gar- 
darsholm, (the old name of Iceland), took with him three ravens 
to serve him as guides. When on the open sea, he let go ono of 
these birds, and if it returned to the ship, this was a sign that 
it saw no land. If, on the contrary, it flew off and returned 
not, they followed its flight, in hopes of reaching the land to 
which it bent its course. At Smorsund where his ship lay ready 
for sailing, Floke had proclaimed a great premium for training 
ravens to this service ; since says the Landnama Book, the sea- 
man had no magnet in our northern lands in those days. As 
this book was written about the end of the 11th century, the 
polarity of the magnet must then have been known in the north 
here, though the proper compass is not expressly mentioned. 
It soon became, of course, a matter of question, what is the 
cause that the magnet, when at perfect liberty to move, always 
arranges itself with its poles towards the north and south. 
The following remarks seem to lead to a satisfactory answer. 
Place two magnets in such a situation, that, by this free motion, 
their north and south poles may be distinguished, it will be al- 
ways found, that, on bringing them near one another, the north 
pole of the one repels the north pole of the other ; and, in like 
manner, that the south pole of the one, repels the south pole of 
the other : On the contrary, the north pole of the one, attracts 
the south pole of the other. This law may be more briefly ex- 
pressed. Similar poles repel^ dissimilar poles attract, one ano- 
ther. From this we conclude, that the globe of the Earth itself 
must be a large magnet, which, in the north, somewhere in the 
neighbourhood of the pole of its revolution, the geographical 
pole, has a magnetic pole of the same sort with that of the mag- 
netic needle which points to the south, and in the neighbourhood 
of the southern geographical pole, a magnetic pole of the same 
sort with that of the magnetic needle which points to the north. 
The north end of the magnetic needle is attracted to the north. 
