John Serson was an English

England

England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

  sea captain best known for his invention of a 'whirling speculum'. This was an early form of artificial horizon designed for marine navigation

Navigation

Navigation is the process of monitoring and controlling the movement of a craft or vehicle from one place to another. It is also the term of art used for the specialized knowledge used by navigators to perform navigation tasks...

, consisting of a mirror, attached to a spinning top, that attempted to remain in a horizontal plane despite the movement of the ship. This device can be seen as a precursor to the gyroscope

Gyroscope

A gyroscope is a device for measuring or maintaining orientation, based on the principles of angular momentum. In essence, a mechanical gyroscope is a spinning wheel or disk whose axle is free to take any orientation...

 used in modern inertial navigation, although it was not itself a gyroscope.

Serson was lost at sea on the HMS Victory

HMS Victory (1737)

HMS Victory was a 100-gun first-rate ship of the line of the Royal Navy, built to the dimensions of the 1733 proposals of the 1719 Establishment at Portsmouth Dockyard, and launched on 23 February 1737.-Construction:...

in 1744.