MAGNETIC BACTERIA
(SFX: water, boat noises, etc.) 
THE INVENTION OF THE COMPASS BEGAN A WHOLE NEW ERA FOR HUMANKIND.  BY
TRACKING THE EARTH'S MAGNETIC FIELD, SAILORS COULD ALWAYS FIND NORTH AND
TRAVEL AROUND THE GLOBE.  BUT THE COMPASS WAS NOTHING KNEW TO A KIND OF
OCEAN BACTERIA SAYS RICHARD FRANKEL.

FRANKEl: These bacteria may have beaten us by about 2 billion years. . . the way they do
it is they actually manufacture for themselves, within their bodies a kind of magnetic
compass needle.

FRANKEL IS A PHYSICIST AT CALIFORNIA POLYTECHNIC INSTITUTE.  HE STUDIES THESE
SPECIAL KINDS OF BACTERIA, KNOWN AS MAGNETOTACTIC BACTERIA.

FRANKEL:  They have been able to make minerals inside themselves much the same way
we make minerals that make bones and teeth. . .they  actually take in iron that they find
in their environment . . . and manufacture the particles of magnetite with in themselves
and line them up in a chain so if you look. . . the bacteria has a backbone.

THAT BACKBONE HELPS ORIENT THE BACTERIA IN THE WATER--NOT JUST BACKWARDS AND
FORWARDS, BUT UP AND DOWN AS WELL--SINCE THE EARTH'S MAGNETIC FIELD IS NOT
ACTUALLY STRAIGHT, BUT AT AN ANGLE TO THE GROUND. BUT THE MAGNETS DON'T JUST
HELP THE BACTERIA GET AROUND--THEY PROVIDE USEFUL INFORMATION FOR HUMANS,
TOO.  WHEN THESE LITTLE BACTERIA BACKBONES GOT FOSSILIZED OVER THE AGES THEY
LEFT A PERMANENT RECORD OF HOW THE EARTH'S MAGNETIC FIELD LAY AT THE TIME.