Bowl-An original treacle compass. Outer: Copper with brass rim. Brass verge ring with stud and pin at centre of glass. Brass moveable ring holding two azimuth sights. Weighted at base with lead. Inner:Copper with brass rim. Black lubber line painted on inside of bowl. Space between bowls could be filled with viscose liquid by means of hole in upper rim.
Card- Mica covered with paper. White with black markings graduated to 1/2 points and graduated to 180 degs. at South through East and West. Hole at centre accommodation pivot bridge. Has four mica fins underside. Dia. 7.5" (19cm)
Needle-Two edge bar needles accommodated in slots in card and pivoted so that they incline to magnetic dip. Lengths: 6" (15.1cm)
Pivot-Inverted type, steel spike in brass mount attached to bridge at centre of card. Pivot rests on agate pivot cap attahed to spring loaded mount secured to base of bowl.
Azimuth sights-On rotatable brass ring. One sight with slit and the other with slit and thread. Height 4.75" (12cm)
Mounted on ACO stand 13.5" (34.3cm)square, O.A. Height 13.5" (34.3cm)