Slate garden sundial

This is an equinoctial sundial, which means that it sits at the same angle as the Earth's Equator. It is also a horizontal sundial - the commonest type (dials set into the wall are simply a variation). This is a very unusual variation with no others known to have survived.
 

The words on the dial are in Latin. This would have been quite usual for 1610 when this was made. 'Labiche Fecit' means 'Labiche made this'. Nothing is known about him.
 

The hours are engraved on a horizontal plate and the hour lines radiate out from the centre point where the gnomon would have sat. The shadow casting edge of the gnomon is parallel to the Earth's axis, and if the dial is correctly set the shadow shows the time.

The moveable circle is for telling time by the light of the moon. The pointer would have been set to the number of days after the last new moon (or to the correct phase). If this not known then the pointer is moved until the small circular window shows the correct phase of the moon as seen in the sky. The time of night could then be read off where the shadow of the gnomon in the centre of the dial (now broken off) fell across the inner ring.