A gyrostat is a massive sphere (or disk) mounted such that the supporting apparatus exerts no torque about the center of the sphere. The earliest gyrostat was described by Bohnenberger [1] in 1817, as shown below. The name gyroscope was applied to this apparatus by Foucault [2] in 1852, although this term has come to imply a sphere or disk mounted with a fixed point on its axis. Lord Kelvin use...
