astronomical regulator, no. 312
Date: 1860
Inventory Number: 2504a
Classification: Clock
Subject:
Maker: William Bond and Son (fl. 1793 - 1977)
Inventor: Richard F. Bond (1827 - 1866)
User: Harvard College Observatory (founded 1839)
User: George Phillips Bond (1825 - 1865)
User: Joseph Winlock (1826 - 1875)
User: Edward C. Pickering (1846 - 1919)
Cultural Region:
Place of Origin:
Dimensions:
191.5 x 61.2 x 61.2 cm (75 3/8 x 24 1/8 x 24 1/8 in.)
DescriptionThis Bond regulator is fitted with a six-legged gravity escapement. Each of two weights is 10 lbs. There are two winding drums. The plates of the movement are conneccted by 4 turned pillars, and the clock dial is connected to the front plate by 4 turned pillars. Behind the back plate, there is a cast-iron arch supported by two cast-iron, grooved pillars. The purpose of the arch is to support the suspension of the pendulum and prevent its motion from affecting the clock movement. At the bottom of each groove, there are holes in the seatboard.
The movement sits on two cast-iron neckpieces. The back plate is held secure to the rear neckpiece by two brackets. The front plate, however, just rests on the other neckpiece.
The pendulum is temperature-compensated and consists of a mercury-filled steel cylinder.
The clock dial is of the regulator form and is made of silvered brass with a "white" matte finish.
There is a glass dust cover for the works.
The clock has electrical contacts and a break-circuit system.
The original clock case has been replaced with a modified one for display purposes.
A box of foundry patterns for Bond clocks includes the patterns for the cast-iron arch and pillars.
An old suspension spring is catalogued as 2504b.
The movement sits on two cast-iron neckpieces. The back plate is held secure to the rear neckpiece by two brackets. The front plate, however, just rests on the other neckpiece.
The pendulum is temperature-compensated and consists of a mercury-filled steel cylinder.
The clock dial is of the regulator form and is made of silvered brass with a "white" matte finish.
There is a glass dust cover for the works.
The clock has electrical contacts and a break-circuit system.
The original clock case has been replaced with a modified one for display purposes.
A box of foundry patterns for Bond clocks includes the patterns for the cast-iron arch and pillars.
An old suspension spring is catalogued as 2504b.
In Collection(s)
SignedEngraved on the dial: WM. BOND & SON, BOSTON. / No. 312
Inscribedon paper formerly attached to dial (now in file): EASTERN STANDARD / TIME
Historical AttributesBond no. 312 was a sidereal regulator acquired by Havard College Observatory (HCO) from William Bond & Son on December 10, 1860 according to the ledger in the Bond Papers. (See also the Annals (1876) and the Director's Report (1861).) It was later estimated to cost $600 ("Memo relating to capital involved in time service" --HUA UAV 630 377). It was mounted in the middle of the Clock Room on a stone pier. The clock was the primary regulator of the observatory and featured a number of the latest improvements developed by Richard F. Bond. It had two pendulums vibrating simultaneously, a new version of a galvanic break circuit, and an isodynamic escapement of Bond's invention.
George P. Bond, the director of HCO, was pleased with the clock and used it for the Time Service and as the observatory's sidereal clock. His successor, Joseph Winlock, had problems with No. 312 and had it repaired by Bond & Son. He noted that "the Sidereal Clock...would vary sometimes one and sometime three minutes per day. It has been repaired by Messrs. Bond & Son, but it is of such an unusual construction and the parts of the escapement require such nice adjustment that it is with extreme difficulty that it can be made to run at all."
In 1866, one of the pendulums was removed, and in 1867, the isodynamic escapement was replaced with another one. In 1868, the clock was converted to Mean Time. By 1880, the clock was used only for differential time measurements and not run continuously.
On November 10, 1881, the Bond day books reference work done by Edmands to put in circuit breakers on Bond 312.
George P. Bond, the director of HCO, was pleased with the clock and used it for the Time Service and as the observatory's sidereal clock. His successor, Joseph Winlock, had problems with No. 312 and had it repaired by Bond & Son. He noted that "the Sidereal Clock...would vary sometimes one and sometime three minutes per day. It has been repaired by Messrs. Bond & Son, but it is of such an unusual construction and the parts of the escapement require such nice adjustment that it is with extreme difficulty that it can be made to run at all."
In 1866, one of the pendulums was removed, and in 1867, the isodynamic escapement was replaced with another one. In 1868, the clock was converted to Mean Time. By 1880, the clock was used only for differential time measurements and not run continuously.
On November 10, 1881, the Bond day books reference work done by Edmands to put in circuit breakers on Bond 312.
Curatorial RemarksExtensively refurbished by Richard L. Ketchen, June 1993.
Discussed with Don Saff, May 30, 2012
Discussed with Don Saff, May 30, 2012
Primary SourcesRichard F. Bond, "Description of Bond's Isodynamic Escapement, for Astronomical CLocks," Brunnow's Astronomical Notices, October 1860; offprint edition (Boston, 1860).
William Bond & Son Papers, Ledgers, 1860-1874, pp. 219, 297, 298, 309 (interleaved sheets), 115. See also the Day book, 10 Nov 1881.
Annals fo the Astronomical Observatory of Harvard College, 8 (1876): 16-17.
Harvard College Obervatory Papers, Harvard University Archives:
----Director's Reports, 1861, 1866-1867, 1874.
----"Memo relating to capital involved in time service," in folder, "Time Service Reports," --UAV 630 377
----HCO to E. C. Pickering, 1 Nov 1880.
William Bond & Son Papers, Ledgers, 1860-1874, pp. 219, 297, 298, 309 (interleaved sheets), 115. See also the Day book, 10 Nov 1881.
Annals fo the Astronomical Observatory of Harvard College, 8 (1876): 16-17.
Harvard College Obervatory Papers, Harvard University Archives:
----Director's Reports, 1861, 1866-1867, 1874.
----"Memo relating to capital involved in time service," in folder, "Time Service Reports," --UAV 630 377
----HCO to E. C. Pickering, 1 Nov 1880.
ProvenanceHarvard College Observatory, from 1860.