Case dimensions: 7 1/4 inches x 5 3/4 inches x 4 3/4 inches high.

For a period of four hundred years, navigators sought to devise a method to use celestial navigation to locate their position. Artificial Horizons have been employed to assist the process, especially when the true horizon is obscured by weather or other elements. In 1868, the mercury bottle and reservoir were designed with a dual paned sighting hood that made it more possible to accomplish this.

With a trough, a steel bottle for holding mercury, and the glass hood, all cased in its original mahogany box.