Marine chronometer · Eight-day marine chronometer

Brockbanks & Atkins 8-Day Marine Chronometer No. 883

Partially verified

According to auction cataloguer Schmitt Horan & Co., this early 19th-century marine chronometer (serial 883) was made by Brockbanks & Atkins in London circa 1830. The source states it features a free-sprung, 13 to 15-jewel reverse fusee movement with Earnshaw's spring detent escapement, a cut bimetallic three-arm Brockbank balance, blued helical balance spring, and diamond endstone. The silvered Roman dial features an up-and-down wind indicator and subsidiary seconds. The brass bowl is gimbal-mounted within a three-tier mahogany box deaccessioned from the American Clock and Watch Museum.

Top-down view of the Brockbanks & Atkins 8-day marine chronometer in its open mahogany box — Schmitt Horan & Co.. Rights pending — permission not yet requested. Original source

Catalogue identity

Source: www.bidsquare.com
Category: Marine chronometer · Eight-day marine chronometer
Form: 8-day marine chronometer
Maker / attribution: Brockbanks & Atkins
Reference: Not recorded
Catalogue / lot identifier: 462
Source-reported date: circa 1830
Source-reported place: United Kingdom
Source-reported serial: 883

Source-reported attribution and specifications are not independent authentication. A listing does not establish present ownership, current display, availability or permission to reproduce.

Object description

Dial and Visible Display

In direct observation, the chronometer presents a silvered dial mounted within a brass gimbal ring inside an open mahogany box. The lower half of the dial features a prominent subsidiary seconds dial, while a viewing deck lid remains open above the bowl assembly. A key is inserted into the front keyhole on the lower box tier, and a brass gimbal lock knob is located on the lower right of the brass gimbal assembly.

According to the auction cataloguer, the signed silvered dial displays Roman numerals, an up-and-down wind indicator, subsidiary seconds, and blued steel spade and poker hands. The dial assembly is housed under convex glass secured by a flat, knurled bezel, resting over an internal movement fitted with a protective cylinder.

Evidence for this section

“Silvered dial set within a brass gimbal ring inside an open mahogany box.”
“Prominent subsidiary seconds dial visible on the lower half of the dial.”
“Glazed aperture or viewing deck lid open above the bowl.”
“Winding or box key inserted into the front keyhole of the lower box tier.”
“Brass gimbal lock knob visible on the lower right of the brass gimbal assembly.”
“signed roman numeral silvered dial with wind indicator, subsidiary seconds, and blued steel spade and poker hands, the movement with protective cylinder and contained in a gimbaled brass bowl with flat, knurled bezel and convex glass”

Reported Movement and Escapement

The internal mechanism is not visible in the sale photograph, and all mechanical details rely on the auctioneer's catalog description. The movement is reported as an 8-day, 13- to 15-jewel, free-sprung reverse fusee caliber winding clockwise, featuring Earnshaw's spring detent escapement with fine adjustment via a screw in the banking piece foot.

The balance assembly is described as a cut bimetallic three-arm Brockbank balance fitted with a blued helical balance spring and diamond endstone. The cataloguer notes that the top plate is signed "Brockbanks & Atkins Eight Days" and "No. 883", with the barrel bridge engraved "London" surrounded by flourishes. The brass bowl is reported to have a shuttered winding aperture at the bottom.

Evidence for this section

“13 - 15 jewel, free sprung, reverse fusee movement winding clockwise, and with Earnshaw's spring detent escapement with fine adjustment by a screw in the banking piece foot”
“cut bimetallic three arm Brockbank balance with blued, helical balance spring and diamond endstone, the top plate signed "Brockbanks & Atkins Eight Days" and "No. 883"”
“the barrel bridge engraved "London", surrounded by flourishes”
“the bottom with shuttered winding aperture”

Casing and Museum Provenance

The chronometer is housed in a three-tier mahogany box measuring 7.25 by 7.25 by 7.25 inches, fitted with contrasting edging, brass furniture, and gimbaled mounting. Pasted inside the lid is a period printed sheet detailing Brockbanks & Atkins "General Directions for the use of Chronometers", described as having a glass cover retained by wooden strips.

The piece is catalogued as having been deaccessioned from the American Clock and Watch Museum in Bristol, Connecticut, and carries a catalogued date of circa 1830. The seller notes prior alterations and repairs to the casing, including a patch in front of the mid section at the lid catch, a split at the rear right of the lid, minor losses to edging, and a wooden replacement where an inlaid serial number plaque was formerly situated below the lock.

Evidence for this section

“all housed in a three tier mahogany box with contrasting edging and brass furniture, ratchet key, the inside of the lid with period printed Brockbanks & Atkins "General Directions for the use of Chronometers"”
“Dimensions: 7.25in x 7.25in x 7.25in”
“directions sheet with minor dirt and staining, and now with a glass cover retained by wooden strips.”
“Deaccessioned from the American Clock and Watch Museum, Bristol, Ct, circa 1830”
“patch in front of mid section at lid catch, inlaid serial number plaque below lock now with a wooden replacement”
“rear right of lid with split, minor losses to edging”

Open research questions

What specific accession records or deaccession documentation exist at the American Clock and Watch Museum regarding the acquisition and provenance of chronometer No. 883?
Does direct examination of the top plate confirm whether the jewel count is 13 or 15 jewels?
What was the original material and numbering of the missing exterior plaque below the lock that has been replaced by wood?

Source evidence

Recorded claims and source quotations for Brockbanks & Atkins 8-Day Marine Chronometer No. 883
Field	Source-reported value	Source quotation
Maker	Brockbanks & Atkins	“Brockbanks & Atkins, London, a good early 19th century 8 day marine chronometer”
Serial Number	883	“serial #883”
Escapement	Earnshaw's spring detent escapement	“Earnshaw's spring detent escapement with fine adjustment by a screw in the banking piece foot”
Box Material	Mahogany	“housed in a three tier mahogany box with contrasting edging and brass furniture”
Dimensions	7.25in x 7.25in x 7.25in	“Dimensions: 7.25in x 7.25in x 7.25in”
Provenance	American Clock and Watch Museum	“Deaccessioned from the American Clock and Watch Museum, Bristol, Ct”
Winding Direction	Clockwise	“reverse fusee movement winding clockwise”
Balance Type	Cut bimetallic three-arm Brockbank balance	“cut bimetallic three arm Brockbank balance with blued, helical balance spring and diamond endstone”
Included Accessories	Box key and ratchet key	“ACCESSORIES: Box Key, Rachet Key”
Reported Mechanism Alteration	Replaced mainspring set-up click	“mainspring set up click replaced”

Visible details

Silvered dial set within a brass gimbal ring inside an open mahogany box.
Prominent subsidiary seconds dial visible on the lower half of the dial.
Winding or box key inserted into the front keyhole of the lower box tier.
Brass gimbal lock knob visible on the lower right of the brass gimbal assembly.
Glazed aperture or viewing deck lid open above the bowl.

Research qualifications

Internal escapement, fusee, balance assembly, and engraved movement markings are not visible in the photograph and rely entirely on auction catalog description.

Photograph identity and source facts were screened before import; rights clearance remains pending.