Some further info from the PHYSICS TODAY (9/98) article, since
there seems to be further interest:

Diamagnetism was first discovered by Michael Faraday in 1846, but
he and Lord Kelvin assumed that there never would be magnets strong
enough for it to be experimented with. In 1939 graphite beads
were levitated (graphite has the largest ratio of susceptibility
to density of diagmagnetics). By 1947 superconductors got into
the game. But as was mentioned, it wasn't until 1991 that intense
enough controllable fields could levitate organics and water.


A diagmagnetic tiltmeter was also made by A.D.Little using principles
similar to their seismometer. (Simon, I., et al, "Sensitive tiltmeter
utilizing a diagmagnetic suspension", Reviews of Scientific Instruments,
39, 1666-1671, 1968).
It used a graphite rod suspended horizontally in the long gap of a
large horseshoe shaped permanent/electromagnet with cleverly crafted
pole shapes. It sensed the rod position optically, which limited the
resolution; but because of the sensitivity of the levitation, it
could detect earth tides at a tilt of 10^-9 radian. A major problem
was the change in the strength of the magnet with temperature. Only
a few were built and tested. 

Regards,
Sean-Thomas


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