Clock

Clock

Any instrument other than a watch for measuring or indicating time, especially a mechanical or electronic device having a numbered dial and moving hands or a digital display.

Industry: Chronometry

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Clock

For recording the arrival time of racing pigeons, developed originally in the 19th century by W. H. Turner. The birds are taken to the point of departure and released at a given time, their homing ...

picture clock

Chronometry; Clock

In the early 19th century it became the fashion to own an oil painting of a town or village scene incorporating the tower of a church or similar building bearing a clock dial. The dial was not part ...

photozenith tube

Chronometry; Clock

Since 1955 Greenwich Observatory near London has employed the photozenith tube (PZT) for checking its standard clock against the stars. Selected stars which transit near the zenith are automatically ...

photographer's clock

Chronometry; Clock

A clock with a large dial and center sweep seconds hand moving over a 0-60 graduated scale, with a subsidiary hand to indicate elapsed time on a second scale graduated 0-60 or 0-100 minutes; ...

pendulum bob

Chronometry; Clock

The adjustable weight at the lower end of a pendulum. The lenticular-shaped pendulum bob, often in cast iron for turret clocks, is probably the most common; it has the advantage of offering the ...

pendulum aperture

Chronometry; Clock

A feature of the design of bracket-clock dials during the first half of the 18th century. A curved hole was cut in the dial above the center to show the small engraved brass disc attached to the ...

pinwheel escapement

Chronometry; Clock

In this escapement, the escape wheel carries pins inserted into one or both sides of the rim and is usually made with the pallets dead-beat. The pallet arms are of different lengths when made to work ...