Armillary sphere.
The primary sphere consists of eight wooden rings. Inside the primary sphere, there are two wooden rings movable around and connected to two brass short axes fixed at the north and south ecliptic poles of the primary sphere. These systems represent the orbs of the Sun and Moon. The larger ring carries a brass disc for the Sun; the smaller has a brass disc for the Moon. In the centre, there is a small terrestrial globe, mounted on a brass equatorial polar axis connected to two little brass arcs. The latter are attached to the two ecliptic axes, so that the poles of the Earth are always pointing to the equatorial poles of the primary sphere. The features on the surface of the tiny Earth are indecipherable. For further information about the cartography and construction of this armillary sphere please refer to the related publication, 'Globes at Greenwich'.