1772 - Two Time Metering Methods for James Cook

James Cook, the famous explorer, 44 years old by now, departs for his second voyage around the world with a copy of famous Watchmaker John Harrison’s H4, that is the watch K1, and three other time-keepers made last year.

¤ Harrison's H4 was the prototype which achieved to meet the accuracy requirement set by the Board of Longitude when crossing the Atlantic ocean. It completed it twice, in 1761 and 1763 - results met with some initial scepticism by the Board of Longitude.

¤ The copy K1 of H4 was made three years ago by Watchmaker Larcum Kendall, 53 years old now. It cost £450 - a small fortune which could buy a gentleman sixty excellent horses with fancy saddles and harnessing. Kendall was one of the six experts appointed by the Board of Longitude for the final trial of H4 seven years ago, and the one chosen by the Board to duplicate it.

¤ This watch looks like a standard watch in the distance but it is much more complex, of course, and much larger. It weighs 3¼ pounds and is 5¼ inches and something in its diameter.

¤ The three other chronometers have been made for £60 each by Watchmaker John Arnold, 36 years old. He has experimented a new escapement to lower cost.

We must see Captain Cook's intent of using a chronometer as an experiment. To be frank, he is sceptical. As everybody knows, this is the lunar-distance method which has lately propagated for the determination of time, hence of longitude. It is painful despite the Nautical Almanac containing pre-calculations thanks to Astronomer Nevil Maskelyne, 40 years old, but it has got a champion in the distinguished Astronomer Royal. Recognise that it costs nothing : this is the same sextant that meters the required angular distance and the altitude of celestial bodies. Furthermore it cannot fails, contrary to the watch.

¤ Maskelyne has become Astronomer Royal in 1765. His path looks like Edmund Halley's one. Having travelled to St Helena island for observing the transit of Venus, he got highly interested in navigation as his elder. On the question of time metering, he has been suspected of a partisan position against Harrison, although his querying seems to stem from pure scientific rigour.

Cook will use the two means in parallel.

He is assisted by Astronomer William Wales, 38. Wales is one of Maskelyne's assistants who, from 1765 on, has computed the lunar distance against different celestial bodies for the purpose of the Nautical Almanac. He is also the one who observed the transit of Venus in Winter 1769 from the Prince of Wales fort on Hudson bay. By the way, he is the one who trialed the first watch produced by John Arnold, 33 then, fitted with an escapement made of sapphire, in the course of the voyage to Hudson bay. A wise adventurer as well as a scholar, he is the right person for a three- or four-year voyage with Cook.

No seafarer before James Cook had such high-level equipment : almanac for several years containing celestial coordinates and pre-calculated lunar distances, sextants, accurate chronometers - it seems that navigation is entering modern times.

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LINKS WITH PREVIOUS CHRONICLES

1714 - The longitude Act

1752 - Accurate Lunar Tables

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IN RETROSPECT FROM TODAY

James Cook, reporting to Admiralty in 1775

NOTE A - On Cook's opinion.

He is quickly won over by the watch K1, so easy to use and which proves to be reliable and very accurate in comparison with the lunar-distance method. K1 will remain the most accurate watch of the period.

Only one in three Arnold's chronometers runs until the end of the voyage.

NOTE B - On K1's fate.

Cook will take again K1 for his third voyage starting in 1776. It breaks in 1779 during the voyage. Repaired by Kendall in 1780, it is used at sea at length until its retirement in 1802 at Greenwich. It has its baptism of fire aboard Victory in the battle of Cape St Vincent in 1797.

NOTE C - On the dissemination of maritime watches.

The only obstacle is the cost of a chronometer, i.e. several hundreds of pounds, without mentioning that having only one aboard is not sufficient for fear of a possible accident. It will take thirty years to see chronometers aboard ships devoid of scientific purposes. At once, it generates a frantic quantity of tries in France as in England. Remaining in England, we have talented Arnold & Kendall. If we cross the Channel, we can find Pierre Le Roy, often depicted as the most critical inventor towards the full-fledged chronometer, and Ferdinand Berthoud. We will deal with the French in other chronicles as the tracks turn to be separate.

Trying to settle the question of price which appears to him as the main obstacle to watch dissemination, Kendall declined in 1770 the suggestion of the Board of Longitude of replicating K1 and proposed a less expensive K2 for £200. It is accepted and this new watch is made in 1771. It proves to be less accurate than K1, and irregular, with a variation of one to three seconds a day as recorded in 1787-88 by Captain William Bligh, 33 then, having it on the infamous Bounty.

Kendall will try a new simplification with the watch K3 built in 1775. It costs £100 but does not meet the requirements of accuracy of the Board of Longitude. It is trialed by James Cook during his third voyage.

Arnold will also produces pocket chronometers from 1772 on for £100 apiece. They behave well as ascertained by Captain William Phipps in his attempt of voyage towards North Pole in 1773. After further changes, Arnold creates a new pathway for marine chronometers from 1777 on.

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CREDIT

William Holl, engraver, after Nathaniel Dance, painter - Captain James Cook - engraving on paper, 1837 - © National Portrait Gallery