Sun Compass

Entry

Compass in gimbals in a wooden box with handles.

The square wooden compass bowl is weighted with lead inside. On one of the sides a sundial is mounted. It consists of a circle divided into two times twelve hours, which can be inclined along a vertical 90 degrees arc. In the middle of the circle, a double string gnomon that can be turned is mounted, with a needle indicating the hour on the circle. The paper compass card is ornamented with animal figures and balanced with white sealing wax beneath, the bottom is a page from the Bible. It is a card made by another manufacturer whose signature has been blacked out. The compass bowl has a brass indicator for the compass card in the side opposite the sundial. It is also dated with pencil on the inside.

This compass allows the reading of the compass error by observation only, without the need for any calculation.¹

Rasmus Dekker repeatedly tried to sell his inventions to the Dutch and French governments between 1791 and 1815, but was turned down on each occasion. They were tested by Hendrik Willem Lantsheer in 1810 and a number of instruments were bought for further testing in 1814, but in 1817 the Navy definitively declared Dekker’s inventions unfit for the service.