Object Name: astronomical regulator with a 24-hour dial
Inventory Number: 2010-1-0022
Description: Unsigned astronomical regulator in a plain pine case with a glazed trunk door. The 24-hour regulator dial is white paint on a thin sheet of zinc.
The high-quality movement has cut steel pinions and four plain pillars between the plates. The plates are damascened and lacquered. It has a Graham deadbeat escapement and Harrison's maintaining power. The pallets are not jeweled. The beat adjustment is built into the escapement; it consists of a slotted screw acting on the pallet frame.
The most interesting feature is the crutch attachment to the pendulum--a single crutch pin held in contact with the pendulum rod by gravity (as opposed to the usual fork-shaped crutch). This single pin makes contact with the side of the pendulum rod and is held there by a counter weight on a rod coming off the pallet-frame beat adjustment. There is also a spring-loaded overload mechanism on the crutch.
There is a temperature-compensating pendulum rod made of zinc and steel. A sleeve with several screw holes at the top of the pendulum allows one to change the ratio of steel to zinc by setting a screw in one hole versus another in order to fine-tune the temperature compensation.
There is an electrical break circuit mechanism on the front plate. It gives a signal every second except at the minute mark (which is "silent").
The winding key is steel.
This regulator is high quality, but not top of the line. It may have been ordered from a scientific instrument catalogue as standard lab equipment.
For further details, please see the captions to the photographs.
Signed: on bearing race on weight-cord offset drum: FAFNIR / MADE IN USA
Inscribed: sticker on case door interior: cleaned, / Jan. 1903 / Nov 1951
note in case written by David P. Wheatland: Gravity Impulse Astronomical / Regulator / Bought from Harvard Astronomy / building (demolished) by DPW / 1957/ cleaned (again) by John Losch / & set up in Boston at #1205 / November 17 1988
note in case written by David P. Wheatland: CLOCK / Bought by DPW / 1957 / from Astronomy / Harvard
Historical Attributes: This astronomical regulator was first owned and used by the Department of Astronomy at Harvard University. Around the time that the Astronomy Department's building was demolished, the clock was relocated to the Jefferson Physical Laboratory of the Department of Physics. In 1957, David P. Wheatland purchased the clock.
Repairs were done around 1960 at Mr. Wheatland's request by Harold Benner in the Cruft Laboratory of the Physics Department. The instrument file has some measured drawings of the clock by Mr. Wheatland on the old letterhead of the Harvard University Graduate School of Engineering Officers' Pre-Radar Training Course, located in Cruft Lab, with E. L. Chaffee as Director.
Mr. Wheatland set the clock up in his home. The clock was later owned by his daughter, Barbara Wheatland. Her estate "returned" the clock to Harvard in 2010 as a gift to the Collection of Historical Scientific Instruments.
Curatorial Remarks: Technical description provided by Richard Ketchen, horologist, March 2011.
Provenance: Department of Astronomy, Harvard University; moved to Jefferson Physical Laboratory 259 after Astronomy's building was demolished. Purchased by David P. Wheatland, 1957 but possibly not removed from Jefferson Lab until 1960; then presumably set up first in Topsfield, MA and later transferred to his Boston apartment in 1988. The next owner was Wheatland's daughter, Barbara (Bee) Wheatland of Sargentville, Maine. Gift of the estate of Barbara Wheatland to CHSI, 2010.