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14. March 2022

WHY WERE CHRONOMETERS ACTUALLY NEEDED?

As is so often the case in the history of clockmaking, it all began with an ingenious inventor named John Harrison. At the age of 20, the British self-taught clockmaker constructed his first pendulum clock, which still shows the exact time and can be seen in the ‘Worshipful Company of Clockmakers’ in London’s Guildhall. Between 1725 and 1727, Harrison constructed two more grandfather clocks. He introduced important innovations such as the ‘Grasshopper escapement’ and the gridiron pendulum. As a result, he achieved the, for the time, enormous accuracy of only 1 second deviation per month!

It was the time of the great voyages of discovery by Wallis, Bougainville and Cook to Tahiti and Australia. Thousands of nautical miles between sightings of land were not uncommon and positioning was anything but ideal. Latitude could already be reliably determined using sextants and astronomical calendars. However, longitude could not, which repeatedly led to grotesque distortions in the nautical charts and meant that descendants were unable to find islands that had already been discovered until modern times.

In 1714, the English Parliament offered a prize of 20,000 pounds to anyone who could find a practicable solution to the ‘longitude problem’. When John Harrison began to take an interest in the problem 10 years later, all previous research approaches submitted to the specially founded ‘Board of Longitude’, which focused on pure astronomical navigation, had failed to achieve any significant success. Renowned astronomers from all over Europe made an effort to do so, in particular using the ‘lunar distance method’, in which the angular distance between the moon and bright fixed stars near its orbit was determined. The astronomical approach was based on tables of star occultations, which could be calculated with sufficient accuracy at the time, but required the moon to be visible and were far too complicated to use at sea.

Columna_Uhrwerk

John Harrison, on the other hand, relied on sufficiently accurate clocks. He had achieved low-friction running of his grandfather clocks with his Grasshopper escapement; lubrication-free wooden gears avoided deviations caused by resinifying oils. Tests by measuring the passage of stars proved that earlier inaccuracies had been reduced to less than a tenth! Harrison then wanted to construct similarly accurate clocks for ships: High swells and lurching in the swell, plus rapid temperature fluctuations irritated the rate accuracy considerably. He presented his first model in 1735. He compensated for temperature fluctuations with bimetal, and ship movements by connecting two identical pendulums with a spring. At the beginning of the voyage, the chronometer was set to the solar time of the known longitude, namely the Greenwich meridian. The geographical longitude could then be calculated precisely from the time difference between the displayed time and the local time (determined by taking a bearing from the sun or celestial bodies).

On his second great voyage around the world, James Cook always had two of these ‘time keepers’ in operation on each ship. In the logbook, the initially skeptical captain called Harrison’s invention his ‘never-failing guide’. With the extraordinary success of Cook’s expeditions, during which he found Tahiti and Hawaii straight as an arrow in the gigantic Pacific Ocean, Harrison’s ship’s chronometer finally prevailed against the superiority of the league of astronomers, including the great Isaac Newton, who for decades spoke disparagingly against Harrison and insisted on their impractical solutions. James Cook’s greatest achievement, the mapping of the Pacific, became so accurate with Harrison’s clocks that his map of New Zealand, for example, was not replaced by a satellite-accurate one until the mid-1990s.

It goes without saying that Patek Philippe, a manufacturer we hold in high esteem, also produced marine chronometers in the past. However, the insights that Harrison gained in reducing friction in the movement can be admired today in the extremely accurate pendulum and table clocks from Erwin Sattler. The movements are so ingeniously mounted that they work extremely quietly, and we are delighted with the latest model under its mouth-blown mineral glass dome.

We do not yet have an exhibit ourselves, but the ‘Columnia Temporis’ can be ordered through us. Interested customers can view this watch directly at Erwin Sattler. This is always possible by appointment and usually includes a short tour of the manufactory, which should not be missed. We really like this completely new interpretation of a grandfather clock, as it offers a clear view of the movement from all sides and the Graham escapement gives Columnia Temporis a running time of one month. Fabulous!

Columna_Fuß

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Stefan Oberleitner

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Uhrmacher*in

mit abgeschlossener Ausbildung im Uhrmacherhandwerk für unser Patek Philippe-Team