Compasses come in various
flavours, and originated in the
12th
century. Apparently
discovered /
invented
independently by both
Chinese and
European mariners, compasses have come a long way.
The first compasses were basically just a piece of
lodestone (a
naturally ocurring magnetic
ore) floated (usually on a stick) in
water. The stone would
align itself toward
North, because the
Earth acts as a giant magnet
with a North-South field. Free magnets align themselves along this
field, and can thus be used for
navigation.
The
evolution of the compass (in Europe at least) was largely due to the
efforts of
English mariners, since England had the largest
navy in the
world at the time. Early compasses only had North and South marked on
their faces, but in time the
tally increased to 32.
Although it was discovered in the
15th century that
magnetic north and
'
true north' weren't always the same, it wasn't until
Gowin Knight
discovered a way to magnetise
steel for long periods of time in
1745
that compass technology seriously progressed.
A modern shipboard compass is usually mounted in a
binnacle, which
will contain pieces of metal and counter-magnets to
neutralise the
effects of the metal in the ship (many ships are
made of metal,
making this
essential).
These days compasses can be found in many forms, from the tiny little
ones you get in
Physics class, to the ones that come mounted in some
Swiss Army Knives. Essentially they're the same as the one's used by
12th century
mariners, and even though
GPS systems and other
pathfinding equipment are becoming more affordable, you'd be an
idiot
to wander into unknown territory without a compass.
Typical compass face layout
N
NW NE
W E
SW SE
S
The principle points (
clockwise from North) are
North,
East,
South and
West. This order is usually taught to
children in the form of an easy
to remember phrase such as "Naughty
Elephants Squirt Water". Children
actually learn this order through a
juvenile corruption of this
easy to remember phrase: "Never Ever Suck Willys". Unarguably good
advice for young children, it's perhaps not the kind of thing
parents
want to hear.