His claim to fame is that, in the 1712, he built a remarkable machine -- called the Bessler Wheel -- which he said was a machine of self-perpetuated motion; by 1717, "he'd convinced thousands of people, from the ordinary to the most prominent, that he had indeed discovered the secret of a self-sustaining mechanism" (source).
The Bessler Wheel was tested repeatedly and rigorously, and it passed every test laid to it.
It was made to do heavy work for long periods, and in an official test it ran continuously for 54 days. The internal design of the machine was always closely guarded by its inventor. Plagued by paranoia and a nasty temper and with no patent laws to protect him Bessler destroyed the machines in a fit of anger and took his secret to the grave. The true motive power behind Bessler’s demonstrations, and the energy source which moved the wheel’s internal weights still remain unexplained. Obviously a machine like this violates the law of conservation of energy, which states that energy can never be created or destroyed but it should then be asked how did Bessler fool so many people for so many years? (Ibid)
In 1717, Bessler himself said the following:
The internal structure of the machine is of a nature according to the laws of mechanical perpetual motion, so arranged that certain disposed weights, once in rotation, gain force from their own swinging, and must continue this movement as long as their structure does not lose its position and arrangement.
And one final thing to consider about this subject:
If by "Perpetual Motion Machine" we mean a device that taps into a natural motion and does work indefinitely without human or animal assistance, the problem is not only solvable but has already been solved in a variety of ways:
* Cox Clock -- a clock that runs forever on barometric pressure.
* Atmos Clock -- a clock that runs forever on small changes in temperature.
* Tidal Power Generator -- harnessing the innate gravitational power of celestial bodies.
* Geothermal Power Generator -- tapping the energy released when gravity condenses matter.
* Nuclear Breeder Reactor -- a machine that produces more fuel than it consumes.
Was Bessler's machine, like these, somehow attached to the very wheelwork of nature? The mathematician Jean Bernoulli wrote:
"...any motion which exists in nature can be used to support a perpetual motion. In these instances such machines cannot be regarded as purely artificial perpetual motion, but rather as a combined perpetual motion because their motion is assisted by nature. I am convinced that Bessler's Wheel is of this type."