LONGINES SIDEROGRAPH ALUMINIUM
Longines Watch Co., "Service Hydrographique de la Marine",
No. 5789255. Made circa 1943.
Very fine and rare aluminium, siderograph with center-seconds, seconds recorder, split-seconds, 36-hour
power reserve indication and stop feature, in a gimballed mahogany deck box.
Deck box with brass bound corners, aluminium gimbal and external start-stop for the chronograph.
Inner: Cylindrical, massive, back secured by five screws, chronograph pushbutton at 8 o'clock,
knob for setting revolving 60 seconds dial at 5 o'clock, winding/setting stem at 12 o'clock, start/stop lever at
10 o'clock, glazed back remo-vable screw-on WEIGHT to work with the gimbals.
Two-tone, silvered, black Arabic numerals, outer minute track, with outer revolving blue chronograph ring,
power-reserve sector below the 12.
21''', Cal. 21.29, rhodium-plated, fausses cotes decoration, 17 jewels, straight-line lever escapement
with beryllium pallet fork, monometallic balance, self-compensating blued steel Breguet
balance spring with micrometric cam-type regulator, chronograph work visible on the back plate.