A magnetic compass made by Kelvin Bottomley & Baird, Glasgow, in 1911.
The method of mounting the compass bowl was suggested by Commander Creagh-Osborne. An outer container is provided fitted with four toes for securing purposes. Two ‘U’ shaped sockets lined with India rubber are fitted inside the container and two trunnions on the bowl engage in these, thus preventing movement of the bowl in azimuth. The space between the bowl and container is lightly packed with horse-hair to damp any vibrations.

The card is of the Chetwynd reduced diameter type and the graduations are black on a white background. A glass lube point filled with luminous compound is fitted, another glass tube similarly filled is attached to the North-point of the card. In this case North is shown in blue and South in red.

The pivot is fitted to the bottom of the bowl and a jewel cup is fitted in the float, which supports the card, after the orthodox method of pivoting nautical compass cards of the day. An expansion chamber protected by a light casing is provided.

A revolving ring, graduated to 360° and having a triangular recess painted with luminous compound, is fitted on the verge of the compass.