h the North American Lakes, passes the Antilles and Cape
St. Roque, till it reaches the South Atlantic Ocean, when it cuts the
meridian of Greenwich in about 65 deg. of south latitude. This line of no
variation is extremely regular, being almost straight, till it bends round
the eastern part of South America, a little south of the equator. The
eastern line of no variation is exceedingly irregular, being full of
curves and contortions of the most extraordinary kind, indicating plainly
the action of local magnetic forces. It begins in latitude 60 deg. south,
below New Holland; crosses that island through its centre; extends through
the Indian Archipelago with a double sinuosity, so as to cross the equator
three times--first passing north of it to the east of Borneo, then
returning to it, and passing south between Sumatra and Borneo, and then
crossing it again south of Ceylon, from which it passes to the east
through the Yellow Sea. It then stretches along the coast of China, making
a semicircular sweep to the west, till it reaches the latitude of 71 deg.,
when it descends again to the south, and returns northwards with a great
semicircular bend, which terminates in the White Sea. Thus it is
demonstrated that in the northern hemisphere the general motion of the
variation lines is from west to east, in the southern hemisphere from east
to west.

A great impetus was given to the study of terrestrial magnetism by the
publication of M. Hansteen's labors; and the various arctic expeditions
sent out by the country did much toward making us acquainted with the laws
of magnetism in the northern regions. One of these expeditions led to the
discovery of the north magnetic pole, or that point where the
dipping-needle assumes a vertical position. The discovery was made by
Captain Sir James Ross, who sailed with his uncle Sir John Ross, in a
voyage undertaken in search of a northwest passage. He left his uncle's
ship with a party for the sole purpose of reaching this interesting
magnetical point, which a series of observations assured him could not be
very far distant. The following extract from his journal communicating his
discovery will be read with interest. Under the date of the 31st of May
1831, he writes: "We were now within fourteen miles of the calculated
position of the magnetic pole, and my anxiety, therefore, did not permit
me to do or endure any thing which might delay my arrival at the long
wished-for spot. I resolved, the