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The Encyclopedia of Horology

Clock · Astronomical regulator

William Bond & Son Astronomical Regulator No. 396

Partially verified

This precision astronomical regulator, numbered 396, was produced in 1868 by William Bond & Son of Boston. The movement incorporates a single-arm gravity escapement invented by Richard F. Bond, alongside a top-mounted conical pendulum beneath a glass dome providing a constant-force remontoire. The 12-inch silvered brass dial displays an astronomical regulator layout with outer Arabic minutes, an upper seconds subsidiary, and a lower hours subsidiary. Housed in a custom bench-made pedestal case with a front reverse-painted sign reading 'Bond's Standard Time', the clock was historically exhibited in the Bond shop window at 9 Park Street, Boston.

Full view of the William Bond & Son Astronomical Regulator No. 396 in its pedestal case
Full view of the William Bond & Son Astronomical Regulator No. 396 in its pedestal case — Skinner. Rights pending — permission not yet requested. Original source

Catalogue identity

Source
www.invaluable.com
Category
Clock · Astronomical regulator
Maker / attribution
William Bond & Son
Reference
Not recorded
Catalogue / lot identifier
500
Source-reported date
1868
Country
United States
Source-reported serial
396

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 Mechanism

The instrument features a 12-inch diameter silvered brass dial signed 'Wm. Bond & Son, Boston', 'Escapement Invented by R. F. Bond', and 'No. 396'. The dial displays outer Arabic minutes, a subsidiary seconds dial divided into two-second increments positioned at the top, and hours indicated on a lower subsidiary dial.

The movement is constructed with two trains and six pillars, incorporating a top-mounted conical pendulum under a glass dome to provide a constant-force remontoire. The single-arm gravity escapement impulses a seconds-beating pendulum originally designed for mercury temperature compensation. A break-circuit provision is situated on the upper right corner of the backplate marked 'Break', 'Close', and 'Break and Close', though the auction condition report records that the break-close device itself is no longer present.

Evidence for this section
  • “12-inch diameter silvered brass dial signed Wm. Bond & Son, Boston , Escapement Invented by R. F. Bond and No. 396, outer Arabic minutes, seconds dial divided in two-second increments at the top and hours on the lower dial”
  • “the two train, six pillar movement with top mounted conical pendulum under a glass dome providing a constant force remontoire, single arm gravity escapement providing impulse to the seconds beating mercury-filled temperature compensated pendulum”
  • “break-circuit provision on upper right corner of backplate and marked Break , Close and Break and Close , powered by a lead weight”
  • “The "Break-Close" device once mounted on the back plate is now gone, with clear evidence of position and original bridges.”

Case and Visual Profile

The regulator stands 71 inches tall in a bench-made pedestal case constructed for display in the Bond shop window. Visible elements include a tall cylindrical glass dome enclosing the vertical conical pendulum mechanism above the rectangular movement housing, mounted atop a light-colored pedestal.

A front-mounted reverse-painted sign on the case reads 'Bond's Standard Time'. The cataloguer notes that an 18-inch removable lower section was used to elevate the clock in the window of the firm's shop at 9 Park Street, Boston, and asserts that No. 396 remains the only example among related Bond regulators to survive with a period case.

Evidence for this section
  • “all housed in a bench made case for use in the Bond shop window and front mounted reverse-painted sign stating, Bond's Standard Time , ht. 71 in.”
  • “Tall cylindrical glass dome enclosing a vertical conical pendulum mechanism atop the movement housing”
  • “Light-colored pedestal case fitted with a prominent dark-framed rectangular panel lettered in gilt: 'BOND'S STANDARD TIME'”
  • “An 18-inch lower removeable section was undoubtedly used to make the clock more visible in the 9 Park Street shop window.”
  • “The present example not intended for use in an observatory, remains the only example with a period case.”

Condition and Alterations

The cataloguer notes that the movement is powered by a replacement single lead weight rather than the two brass ball weights likely used originally (as seen on Bond No. 395). In addition, while the temperature-compensated seconds-beating pendulum remains present, its mercury filling has been removed.

Retained components include the original glass dome covering the conical pendulum, the glass box over the movement and dial, the conical pendulum, hands, and winding key. Although the auctioneer describes the clock as being in 'excellent mechanical condition', this represents a subjective seller appraisal.

Evidence for this section
  • “The two brass ball weights probably once used to power the clock (and still found on Bond No. 395) are now replaced with a single lead weight.”
  • “396 retains the original glass dome protecting the conical pendulum, glass box over the movement and dial, conical pendulum, second's beating pendulum (mercury removed), hands and winding key.”
  • “Bond Regulator No.396 is in excellent mechanical condition.”

Open research questions

  • What physical or electrical remnants of the break-circuit contact system remain visible on the backplate bridges?
  • Does archival documentation confirm whether No. 396 originally operated on a single weight line or a twin-weight system identical to No. 395?
  • What primary materials and joinery characterize the bench-made pedestal case and its 18-inch removable riser?

Source evidence

Recorded claims and source quotations for William Bond & Son Astronomical Regulator No. 396
FieldSource-reported valueSource quotation
Maker and DateWilliam Bond & Son, Boston, 1868“William Bond & Son, Boston, 1868”
Dial SignatureWm. Bond & Son, Boston, Escapement Invented by R. F. Bond and No. 396“12-inch diameter silvered brass dial signed Wm. Bond & Son, Boston , Escapement Invented by R. F. Bond and No. 396”
Escapement and RemontoireSingle arm gravity escapement and conical pendulum remontoire“top mounted conical pendulum under a glass dome providing a constant force remontoire, single arm gravity escapement”
Pedestal SignBond's Standard Time“front mounted reverse-painted sign stating, Bond's Standard Time”
Total Height71 in.“ht. 71 in.”
Movement ConstructionTwo-train, six-pillar movement“the two train, six pillar movement”
Reported Exhibition HistorySmithsonian Institution (1982–2000)“Exhibited at the Smithsonian 1982-2000”
Reported Provenance ChainWilliam Bond & Son; Suren H. Hekimian by descent to the consignor“William Bond & Son; Suren H. Hekimian by descent to the consignor.”
Included AccessoriesFive custom-built foam-fitted shipping crates; ephemera pictured does not accompany lot“Accompanying the lot are five custom built foam-fitted shipping crates designed to safely transport Bond 396 and all components. Ephemera pictured does not accompany the lot.”

Visible details

  • Tall cylindrical glass dome enclosing a vertical conical pendulum mechanism atop the movement housing
  • Silvered regulator dial enclosed within a glazed rectangular movement case
  • Light-colored pedestal case fitted with a prominent dark-framed rectangular panel lettered in gilt: 'BOND'S STANDARD TIME'

Research qualifications

  • The auction condition report states that the break-close device formerly mounted on the backplate is missing
  • Mercury has been removed from the seconds-beating pendulum
  • Currently driven by a replacement single lead weight rather than the probable original brass ball weights

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

Consulted source

Sold at Auction: The Bond Shop Astronomical Regulator No. 396, William Bond & Son, Boston, 1868, with Single Arm Gravity Escapement and Remontoire Inven

Reviewed 2026-10-21 · Record b02f3ee3bb

Terms in this record

Glossary explanations for terms named in this object’s record.

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