The pelorus is an instrument to make relative bearings against ship’s ahead or against compass heading. So it’s not a compass. The compass rose looks like a normal wind rose, but there is no compass needle.
The gimbaled brass instrument with brass rose is mounted in a mahogany case with tooth corner connection. On top of the rose is a bearing device with V and threat sight. The instrument stays in vertical position by a lead weight at the underside.
This nice instrument is complete and in a good condition. Maker’s name on the rose.

Catalog: NM.5-33
Date: c. 1920
HWL case: 22x29x29 cm
D rose: 19 cm
Signed: T.S. & T.D. Negus, New York
Origin: USA
Condition: in good and working condition, wear consistent with age and use