Roof artificial horizon

A rectangular cast-iron trough with a pouring hole at one corner, and a black-painted brass-framed roof-shaped cover. Two sides of the cover have clear glass panels at an angle of 90 degrees. Accompanying the instrument is a polished steel mercury bottle with a threaded funnel-shaped cover and a threaded stopper. It is used for storing the mercury when the instrument is not in use.

The artificial horizon is contained in a fitted rectangular mahogany carrying box with a brass plate for securing the mercury bottle.