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Longitude, the Greatest Scientific Problem of the 18th Century - Page 3

© Wesley Colley

Harrison finally (after 19 years) emerged with his most sophisticated effort yet, H-3, which was somewhat smaller than the first two (though still weighing 60 pounds) and truly a marvel. However, during the construction of this masterpiece, Harrison had occasion to enlist the services of a brass artisan named John Jeffreys. In his association with Harrison, Jeffries presented him with the gift of a pocket watch that used some of Harrison's advances within it. It kept such incredibly good time that Harrison decided he could produce a much smaller version of his clock, and returned to his lab. There, he rendered in just a few years his piéce de rèsistance, H-4, a much smaller device which employed diamond and ruby gear teeth to reduce friction. Although it was inches in diameter, not feet, this device did require some lubrication.

Here, at last, was a timekeeper small enough to tote to sea, and reliable enough to determine longitude even on a long voyage. Harrison consulted the Board of Longitude, which by now had become a bit wary of his delays, particuarly since its staff included astronomers eager to establish the lunar method and claim their prize.

At length, Harrison got his trial at sea, which H-4 passed with flying colors. Upon his return to London, the board was underwhelmed and insisted a more rigorous test be done, with four observers aboard and with a member of the Board (an enemy astronomer) stationed in Jamaica to test the watch's accuracy. Needless to say, the astronomer was not about to concede defeat and refused to take observations despite a cloudless sky. Finally, the Board did agree that the watch had performed well enough, but it wasn't really "Practicable" because there was only one. To claim the prize, Harrison would have to construct two duplicates without the luxury of having his first model to go by nor even drawings to consult.

He did build another one in about five years, but by then he was 79 and quite decrepit. Harrison's son William had become a friend of King George III. The king brought the Harrisons and their evidence before Parliament, which rightly awarded them the prize money forty years after H-1 had apparently deserved it. The astronomers of the Royal Society, stubborn to the end, refused to follow Parliament's lead and never did confer the honor of prize-winner on Harrison. Harrison might have taken solace, however, in the fact that by the mid-1800's the lunar method had largely died out, while watches incorporating his advances persisted well into the 20th Century. Moreover, many thousands a year visit the Maritime Museum in Greenwich to marvel at his still-running clocks.

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