1920s early round silver vintage Longines watch

An early round silver vintage Longines watch. The case measures 35 mm in diameter with hinged lugs. The case is signed AB (Arthur Baume, director of Longines, with rights to Longines in the U.K.) and hallmarked London 1923. The case has a hinged back and hinged protective dust cover for the movement. The Swiss movement is signed Longines with 15 jewels and has centre sweep seconds. The white enamel dial has black Roman numerals with a red twelve. The dial is signed Longines above the centre.