Russian silver open faced deck chronometer watch Circa 1878

Silver chronometer by Johan Wirén
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A very fine and rare Russian, silver, deck chronometer, circa 1878. With Earnshaw’s footed spring detent escapement, free sprung helical balance spring and power reserve indication. The movement made by Kullberg, the case hallmarked London 1878-1879.
A polished case with gold hinges. White enamel dial, bold radial Roman numerals, outer minute track, subsidiary seconds, power reserve indicator at 12 o’clock. Blued steel spade hands.
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A frosted gilt, full plate movement, 17 jewels, ringed cylindrical pillars, fusée and chain, Harrison’s maintaining power, Earnshaw type spring detent chronometer escapement, jewelled locking stone, cut bi metallic compensation balance with peripheral meantime and temperature adjustment screws (balance staff broken), free sprung blued steel helical balance spring with terminal curves, diamond end stone, jewelled to the third wheel with screwed chatons.
Dial and movement signed.
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Diameter: 62 mm
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Signed: Johan Wirén  Saint Petersburg