This two-day chronometer has an Earnshaw-type spring detent escapement and bimetallic compensation balance, with cylindrical brass compensation weights on the rim segments at about 85° to the arms and a blued-steel helical balance spring. The early service history of this chronometers service remains unknown. It was acquired in December 1943 from the Composite Signals Organisation base (one of the government’s radio listening stations) at Kilindini Harbour (the port at Mombasa in Kenya), having come from the fleet repair ship HMS Alaunia.
It was taken on charge on 1 February 1944, valued at £27. Its condition was reported as ‘fair, requires overhaul’. The twentieth-century box is non-standard, with no handles on the sides, and brass pivot screws with knurled nuts (probably made from electrical terminals), screwed directly into the wood of the front and back of the box and pivoting the chronometer bowl in one plane only, without any gimbal ring. Fixed to the back inside the top of the box is a small brass bridge-like piece for retaining the winding key (now missing). An adhesive blue and white plastic label inside the top of the lid is printed with: ROYAL GREENWICH OBSERVATORY / INVENTORY No. 04749.
In 1944 the chronometer was sent to Montreal, returning in 1946. It was transferred to the NMM collection on the closure of the RGO in 1998.