Time Measurement

 

On Display

Galileo's pendulum clock, c 1642.

This 19th century model is based on a drawing made by Galileo's (1564-1642) friend and biographer Viviani (1622-1703) of a pendulum clock, which Galileo designed just before his death and which was partly constructed by his son Vincenzio in 1649. It

 
Balance spring pocket watch in silver case, 1675-1679.

An exquisite watch by the master maker Thomas Tompion showing an early example of the balance spring mechanism.

 
Pocket shepherd's sundial, French, 19th century.

Crude sundials of this type were used in the Pyrenees as cheap alternatives to watches until well into the 20th century.They indicate time from the sun's altitude, which is also dependent on the latitude and the season of the year. This instrument i

 
Pocket sand glass, c 1500.

Sandglasses are used to measure out a precise amount of time by the regular flow of sand (or other granular material of uniform size) through a small hole. They were probably invented in the 12th or 13th century and were used to regulate the length o

 
Hipp chronoscope, Swiss, 1888.

Produced by Matthias Hipp of Neuchatel, Switzerland, this device was used to measure short intervals of time to within 1/1000th of a second. Its timekeeping element is not a pendulum but a metal reed which vibrates 1000 times per second above an esc

 
Early Egyptian water clock, 1415-1380 BC.

The original of this plaster cast (which is held in the Cairo Museum) was found at Karnak Temple, Upper Egypt, in 1904, and dates from the reign of King Amenhotep III (1390-1352 BC). It is made of alabaster and was probably used for indicating the pa

 
Egyptian shadow clock, 1925.

This primitive altitude sundial is of a type which was still in use in Egypt during the first quarter of the 20th century although it operates on the same principle as the Egyptian shadow clocks of almost three millennia earlier. The horizontal bar o

 

The Egyptians used a star clock or merkhet to measure the time at night.

 
'Sinking bowl' water clock, Saxon.

This is a copy of the original bronze bowl found in a bog in County Antrim, Northern Ireland. The bowl has a small hole in the bottom, and in use it was placed on the surface of water until, after a certain interval of time, it sank. The interval in

 
Early German watch and watch movement, 16th century.

The watch movement shown on the left dates from the first half of the 16th century and is made mainly of steel. Because the balance has no spring it does not have a natural frequency of vibration and the timekeeping depends on the driving force. With

 
Four-way sand glass, Italian, 17th century.

This set of four sand glasses is mounted in a pivoted brass frame so that it can be inverted as required. They measure intervals of a quarter, half, three-quarters and one hour, and are of a type formerly used by preachers for timing their sermons.

 
Tibetan priest's time stick from Darjeeling, India, c late 19th century.

This time stick from Darjeeling operates in the same way as a column sundial. It has eight sides, each of which is graduated in ghatis (of 24 minutes duration), and marked with the name of the month, four sides having two names. To find the time a me

 
'The smallest watch in the world', 1929.

This Jaeger- LeCoultre '101' wristwatch movement introduced in 1929 remains the smallest mechanical wristwatch movement ever made. It was put into series production and remained available at least until the 1950s. It comprises 98 parts, measures 14mm

 
Bracket clock, French, c 1680.

An early example of a pendulum clock made by Isaac Thuret (d. 1706), clockmaker to King Louis XIV (1638-1715) of France. The first commercial pendulum clocks were made in the Netherlands in 1657, under a licence or 'privilege' according to the design

 
Bracket clock, Dutch, c 1675.

An early example of a pendulum clock made by Johannes van Ceulen of The Hague, Netherlands. Van Ceulen made clocks for Christiaan Huygens (1629-1695) and this clock follows Huygens' design. The pendulum is suspended between curved 'cheeks', so that i

 
Huygens' pendulum clock, 1657.

This model was made according to the first published account and illustration of Huygens' pendulum clock. Huygens was aware that the period of the pendulum was not completely independent of the arc through which it swung and in his earlier clocks he

 
Two pillar clocks, Japanese, 17th and 19th century.

Japanese pillar clock with single foliot balance and iron movement (weight missing)

 
Hamilton electric wristwatch, 1957.

Launched by the Hamilton Watch Company of Pennsylvania, USA on 3 January 1957, this was the world's first commercial electric watch. A significant advance in the development of electric timekeeping, it took more than ten years to develop. Among the m

 
Bain electric clock, c 1850.

Alexander Bain was a pioneer of electrical horology and the first person to produce electric clocks commercially. This is an example of one of his later designs with a magnetised pendulum which swings into coils attached to the side of the case. A sl

 
Bulova 'Accutron' wristwatch, c 1962.

When the Accutron was introduced in 1960 it was described as the first electronic watch but it also had another revolutionary feature, the time keeping was controlled by a tuning fork. The tuning fork vibrated 360 times per second and the vibrations

 
Rolex 'Oyster Perpetual' wristwatch, 1931.

This is an example of the first really practical and long lasting self-winding wristwatch which was introduced by Rolex in 1931. A small movement of the wrist causes a semicircular weight to rotate and wind the mainspring. This keeps the spring at op

 
Longines 'Ultraquartz' quartz analogue wristwatch, 1969-70.

Early quartz crystal watch but one which operates on an entirely different principle. The frequency of the quartz crystal is not divided down electronically but is used to control and correct the vibrations of an arm by means of a cybernetic circuit.