[ Nicholas Simons wrote in 040220 MMDigest:

> Mention was made of Watt's planetary gear drive on the crank of his
> beam engines.  This is an ingenious and simple method of increasing
> the effective inertia of the flywheel.  The flywheel rotates twice as
> fast as it would otherwise and therefore has four times the inertia.

As I recall, Watt did this because a competitor claimed a patent on the
crank.  This kind of chicanery was the eventual reason for creation of
the concept that some devices are so universal, they are public domain
and can't be patented.

Larry Mayo