ed I remember that. in fact here in the usa someone marketed a wheel balancer for cars based on the same theory. it sandwiched between the wheel and the hub. it worked but occasionally would explode shooting out ball projectiles flattening the tire. LOL The idiots made the housing for the balls out of plastic and in those days plastic took a dive in a real hurry. well enough telling everyone what an antique I am.
LOL D
PS a mercury filled version of that is still used on diesel engines for torsional vibration reduction.
Very interesting method, relly never heard or use this kind.
Necessity, The mother of all innovation.
