HELICAL FREE SPRUNG Hairspring Lever Fusee Patent Union Chronometer Antique British Pocket Watch

Good pocket chronometer in 18k golden case.
London hallmarks date it to 1873.
Diameter is 52 mm, weight is 127 gramm.

Movement is signed by "Arnold & Lewis, late Simmons", "Patent Union Chronometer" and bears serial number 3133.

It's one of the latest watches being made according Morton's chronometer design.
Patent Union Chronometer, a development of George Morton's original Patent No 2434, October 1857. As development took place the watches are variously engraved, if at all: Morton's Patent; Morton's Patent Improved; Patent Chronometer; London Patent Chronometer; and finally Patent Union Chronometer, all numbered within the same sequence, the last known number being just over 3000. See also Randall, The Time Museum Catalogue of Chronometers, items 127 and 128.

The keyless movement is 3/4 plated, driven by fusee and is equipped English lever escapement.
It features nice diamond endstone, helical free-sprung hairspring (factory adjusted to best performance and lacking any adjustment regulator).
The chronometer balance wheel is thick and heavy, with big golden screws.

Case bears London hallmarks for year 1873 and maker's mark CG for Caroline Green.
Interesting piece of British chronometry.




Condition
The watch appears to be in good condition.
Movement functions as it should.
Dial seems to be in good condition.
Case has common period wear without significant flaws.
Very nice piece in good condition.