All this can be obtained both by shifting the staff along the cursor of the gimbals and by varying the mass of the counterweight by adding or removing some disks.
The gyroscope can be made to rotate rapidly by pulling one end of a strong silk or cotton string wound around the other end which is lodged in a small hole provided for that purpose.
Once the gyroscope is rotating, it is possible to study the phenomena that appear in presence or absence of an external moment in different situations.