Masons Antiques has dated this piece to the 1800s.
Made by P.SALVADE of LIVERPOOL.

A suberb mahogany case with ebony and boxwood stringing to the outer edge.
It has just been totally overhauled and re-calibrated.
An 8" engraved silvered dial with cast brass bezel.
Dimensions:
Height 39" (100cm)
Width 10" ( 26cm)
Depth 2" ( 5cm)
Masons Antiques has dated this piece to the 1800s.
You can view the stock and full dealer information on the Masons Antiques Profile Page