NavList:

   

Reply

Alex has remarked on some of the deficiencies of Sobel's book "Longitude".

If he trawls through the list's archives (under "Sobel", perhaps?) he should find several more.

Sobel was not a navigator or a historian, but a journalist, who happened to 
attend a symposium on longitude at Harvard in 1993.
Incidentally, that symposium was the basis for that marvellous book "The Quest 
for Longitude", ed., William J H Andrewes, published
by Harvard in '96, which I thoroughly recommend..

Sobel's book is a historical romance, with a hero (Harrison) and a villain 
(Maskelyne). It has little connection with the facts, or
the truth. Sobel fails to understand what she writes about, as Alex's 
quotation indicates (and many others)

As for Shovell's disaster of 1707, when his fleet of four ships piled up on 
the Scillies in the dark with the loss of 200 lives, it
was a failure to know, not his longitude, but his latitude. In cloudy weather, 
coming home from Spain, he had succesfully passed
West of Ushant without sighting it, and had to judge when to turn from heading 
North, to NorthEast to aim up the English Channel for
Plymouth. That timing was crucial, and Shovell left it far too late.

In cloudy weather, with no view of the sky (a common enough state of affairs 
in the Western Approaches), celestial navigation was
completely irrelevant. If he had been carrying a perfect chronometer (not 
invented until 50 years later) it would not have helped
him a bit. What Shovell neglected was that elementary tool that had been 
drilled into mariners for years: he didn't heave-to at
intervals to take soundings with his dipsey (deep-sea) lead. Admitted, that 
was a tricky thing to do when four ships were in close
convoy, in the dark. Instead, he chose to rely on his dead-reckoning, as 
Wolfgang Koberer states. And there's a time limit over
which it becomes folly to rely on dead reckoning, with no observations to back 
it up. With hindsight, Shovell would have done better
to shorten sail, and take off his convoy's way until the morning.

It's true that the Shovell disaster raised much public alarm, which led 
indirectly to the Longitude Act and the Longitude Prize and
then to the Nautical Almanac and to Harrison's chronometer. But it is quite 
wrong to attribute the disaster on the Scillies to
ignorance of longitude, as Sobel does.

Look at another part of that story, as told by the credulous Sobel. But first, 
here's Rupert Gould's version, as told in a footnote
to his book "The Marine Chronometer". "A story was current, long afterwards, 
that a seaman of the flagship had kept his own
reckoning, which showed that they were in a dangerous situation, and that on 
making this known to his superiors he was hanged for
mutiny, there and then. Credat Judaeus Apella."

An unlikely tale, indeed. No captain, not even an Admiral, had such powers of 
summary justice. And certainly would not behave so
rashly within a day or so of arriving at a home port. Compare how Sobel tells it-

Shovell "had been approached by a sailor, a member of the Association's crew, 
who claimed to have kept his own reckoning of the
fleet's location during the whole cloudy passage. Such subversive navigation 
by an inferior was forbidden in the Royal Navy, as the
unnamed seaman well knew. However, the danger appeared so enormous, by his 
calculations, that he risked his neck to make his
concerns known to the officers. Admiral Shovell had him hanged for mutiny on the spot".

Here, you can see shoddy journalism at work, retelling a popular fable as unquestioned fact.

Alex should be aware of the dangers of apoplexy as he continues to read through "Longitude".

George.

==========

contact George Huxtable at george@huxtable.u-net.com
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.

   

Reply