Images(12)

Tall case clock

Date1760-1770

Artist/Maker John Berridge

OriginEngland, Lincolnshire, Boston

MediumMahogany, oak, and glass; brass, silvered brass, steel, and iron.

DimensionsOH: 82"; OW: 20 1/2"; OD: 10"

Credit LineMuseum Purchase

Object number1954-931,A&B

DescriptionAppearance:
Case:
Arched bonnet with square plinths for finials at front corners and chamfered front corners; arched, molded door to trunk, stepped base molding.

Dial:
Round 12” diameter silvered brass dial with large engraved Arabic minutes dial and single minute hand; small Arabic seconds dial in top portion of dial; lunette aperture for Arabic hours above single winding hole and maker's name "John Berridge/ Boston" in cursive.

Movement description:
Eight-day weight driven laboratory regulator timepiece to measure elapsed time in seconds, minutes, and hours. Movement measures 11 ¼” H x 4 1/8” W. Plate thickness is 0.125”. Distance between plates is 2 3/8”. Precision movement for high accuracy time measurement contains a dead-beat escapement, bolt-and-shutter maintaining power so timepiece does not stop during winding; six plate pillars (vs usual 4) for maximum movement rigidity; all gear pivots protruding through plates are covered with brass covers to prevent oil from contacting dust which will wear and slow down timekeeping; movement bolted to seat board via bolts from underneath center into right angle brass brackets fastened to back plate; center, third and escape pinions of eight leaves (not six) for smoother operation. Plate pillars are secured to front plate via sliding latches not the usual pins. All gears in movement have four spokes except for escape wheel which has six.

Weight pulley is standard cast-brass pulleys with riveted stirrup. Brass and steel gridiron-type pendulum to compensate for thermal expansion with cast-iron bob of lunette shape measuring 6” H x 6” W. The pendulum contains a mechanism for extremely precise length adjustment in order to achieve timekeeping accuracy. The overall length of the pendulum is 45”. The weight is cast iron with a cast in loop for the pulley hook. The weight is 9” long. It is 3” diameter at the top and 2.6” diameter at the bottom.

No strike train, winding drum, or bell.
Label TextRegulator clocks, the most accurate timekeeping devices, were often owned by master clockmakers to set other clocks by and by scientists who needed precision for their experiments and studies. The inclusion of George Graham’s deadbeat escapement rather than an anchor escapement provided greater accuracy. Unlike most clocks, the large hand on this clock is for the seconds, the smaller hand for the minutes, and the lunette under the seconds hand for the hour. The case, dial, and mechanism of this regulator are streamlined to focus on precision timekeeping.

The round sheet dial on this clock was less expensive and simpler to read than the more ornate brass dials. An English innovation during the 1760s that appeared on many English and American clocks, brass plates, silvered over their entire surfaces, were used to create round, square, or arched sheet dials. The unusual round dial was first used by a clockmaker in Derby, England, about seventy miles west of Boston where John Berridge produced this example. While that maker believed that using a square dial for a clock that had a rotative (round) hand function was illogical, his innovation was never fully accepted except on regulator clocks until well into the 19th century.
Markings"John Berridge/ Boston" in cursive in center of dial under hours lunette.

Exhibition(s)