Andrew Charles Ltd has dated this Silver Waltham Pocket Watch to the 1870s.

Case diameter 49.5mm.
The Waltham watch company was founded by Aaron Lufkin Dennison in 1849 in Roxbury Massachusetts. In 1854 they moved to Waltham Massachusetts and the Waltham watch company was born.

The casemaker 'AB' was Alfred Bedford who succeeded to the managership of Waltham in Britain when Seeland left. Bedford subsequently became the general manager in Europe of the Waltham Watch Company - Holborn Circus, London.
Andrew Charles Ltd has dated this Silver Waltham Pocket Watch to the 1870s.
You can view the stock and full dealer information on the Andrew Charles Ltd Profile Page