But now remove the gyrostat from the frame, and set the wheel in rotation.
There is, however, a great difference between the earth and the gyrostat.
Here is a gyrostat (Fig. 23) something like the earth in shape, and it is at rest.
It is not precessing, so you know that the weight W just balances the gyrostat F.
Now close observation will give you a simple rule about the behaviour of a gyrostat.
Figure 15 shows one form of gyrostat mounted on a horizontal frame, held in the hands of an experimenter.
The gyrostat is now replaced on its pivots in the frame, with its axis vertical, and moved about as it was before.
At present the balance-weight is so placed that the gyrostat would fall if it were not spinning.
In fact, the microscope and all other objects in the room are going round the gyrostat frame.
In the theoretical discussion of the general motion General motion of a gyrostat rolling on a plane.