Year of manufacture1970
THOMAS EARNSHAW POCKET
CHRONOMETER WITH Z BALANCE SILVER
"Pocket Chronometer with "Z" balance" Thomas Earnshaw,
Invenit et Fecit, No. 486 of the sort/2827.
Very fine and rare, silver pair-cased pocket Chronometer with
Earnshaw's spring detent escapement and Earnshaw's "Z"
OUTER: two-body, polished. INNER: two-body, "bassine",
White enamel, radial Roman numerals, outer minute track,
subsidiary seconds. Gold "heart and poker" hands.
42 mm. secured by screws, gilt full-plate with cylindrical
pillars, fusee and chain with Harrison's maintaining power,
Earnshaw spring detent escapement, escape wheel jeweled
with endstones in screwed chatons, Earnshaw's "Z" bimetallic
compensation balance with sliding timing weights and two
steel mean time screws, single-footed clock with endstone in
screwed chaton, free-sprung blued steel helical balance-spring.