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There's a poignant little story that appears as a footnote in the history of
the "Trigonometric Survey" in the 1790s.

The survey had revealed that the Isles of Scilly were misplaced in latitude
by 2' which, as they said at the time, "may not perhaps be considered
extraordinary," but even at this late date the published longitude of the
Scillies was in error by a whopping 26.6'. Note that this is at the end of
the eighteenth century, long after the longitudes of such important points
near the mount of the English Channel should have been settled... As the
commentator in the survey puts it politely, "but how, in a maritime country,
like our own, where chronometers are in such constant use, so great an error
in the longitude should have remained undetected, except by one person, is
surprising." Yeah, surprising!

The error in the longitude of the Scillies had been previously noted by
Captain Joseph Huddart who had visited the islands, some years earlier, and
here's where it gets poignant. Huddart had visited the exact spot on the
beach where Sir Cloudesley Shovell, shipwrecked with a loss of thousands of
lives in 1707 due to poor navigation, had been buried in the sand by the
locals. Huddart had brought with him one of Arnold's chronometers, a premier
example of the great invention of the age, and right there, standing by
Shovell's temporary grave, Huddart carefully measured the longitude by
observing equal altitudes of the Sun. His result differed only about one
mile from the correct longitude recently determined by the trigonometric
survey.

Incidentally, among the many items recovered from the wreck site of
Shovell's flagship, the Association, were the faces of several pocket
watches --expensive, primitive forerunners of the delicate chronometer that
Huddart held in his hand by Shovell's grave decades later.

 -FER



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