This gyroscope, all brass except for the heavy rectangular basement (13.5 x 20 cm), which is polished mahogany, is composed of two concentric rings (diameters 14 and 12 cm), one of which placed inside the other, and a flywheel (diameter 6.3 cm) made up of a disk surrounded by a toroidal ring.
The rotation axis of the outer ring is vertical since its two suspension pins are attached to the ends of two narrow but thick horizontal plates, one of which attached directly to the basement and the other projecting from the top of a vertical column (height 18 cm).
The rotation axis of the inner ring is horizontal, since its suspension pins are attached to the ends of the horizontal diameter of the outer ring..
The flywheel is suspended inside the second ring by means of the sharply pointed ends of a steel rod which goes through its centre normally, between the notches of two pins attached to the ends of the diameter perpendicular to the rotation axis of that ring.
In this way, the rotation axis of the flywheel can assume any direction in space.
By winding a strong cotton or silk string to the rotation axis and pulling it sharply, the flywheel begins rotating rapidly.
Murani (1906), Vol. I, p. 189
Perucca (1949), Vol. I, p. 323
Turner (1983), p. 75