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.

James Watt also invented the Watt's linkage, which is another brilliant
but widely misunderstood mechanism.  In the early days of steam there
were no machine tools large enough to machine long flat surfaces such as
those required for piston rod slideways.  The Watt's linkage consists
of three pin-jointed links that create a straight line motion without
any recourse to a straight edge.  It is difficult to describe on paper
but elegant to watch.

Regards to all, Nicholas Simons.
Great Britain.

 [ Brother John Rhodes found a discussion of Watt's linkage
 [ at http://www.ams.org/new-in-math/cover/linkages2.html
 [ and also a nice animation of the Peaucellier cell at
 [ http://carol.wins.uva.nl/~leo/cinderella/peaucellier1.html
 [ -- Robbie