Clinometer?. A vertical shaft carrying a dial, graduated by semi-circles 0-180, 0-180 and in hours, which can be tilted to latitude against a scale carried on its underside. Hinged sights are fitted to an alidade pivoted at the centre of the dial. One of the vanes caries crosswires, and the other a curved plate with crossed slits. A pointer attached to the lower end of the vertical shaft indicates the bearing of the sun on the bearing plate.