Bessler's idea solved

[Fletcher]

Sure - a pneumatic engine [becoming fashionable again] - trouble is you have to compress the air.

The french guys [name escapes me at the moment] 50 ft wheel was an ambient pressure driven wheel IINM.

Edit : Aldo Costa

[jim_mich]

Is there an efficient mechanism that runs off a pressure difference?

Yes, a turbine, a windmill, a pneumatic air motor, and similar devices.

[satanspawn]

I see a lot of egocentrics here that simply cannot accept the fact that perpetual motion is impossible. As someone else mentioned, the second you build your little gravity machine you might as well book your trip to Stockholm to accept your Nobel prize. Hasn't happened and will never happen! Bessler built a really, really cool contraption - that is not in doubt. However it was NOT a perpetual motion machine. If you "believe" it was then I'd like to tell you a little story about a man that could walk on water (defying the laws of physics). There are people that wrote that it happened.... thus you must "believe" it.....