Heading for Trouble

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Heading for Trouble

• The Perils of Navigation

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The first most principal thing for any
seafaring man or traveller, is to know toward
what part of the Earth he meaneth to go.
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Gresham College and the British Society for the
History of Mathematics present Stephen
Johnston History from below mathematics,
instruments and archaeology Thursday 3 November,
6pm
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The pilots took the north, marking it, and found
that the compasses northwested a full point and
the sailors were fearful and distressed. The
Admiral ordered that the north again be marked
when dawn came, and they found that the compasses
were correct. The cause was that the North Star
appears to move and not the compasses.
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He that diligently observes the variation, finds
(as I say) no prejudice in it, only it requires
daily, or once in two or three days half an hours
work, and this labour it doth abundantly
recompense for by this means he knows at the
present how to direct his Course, and for the
future he knows when he draws near to any of
those places where such observations were made,
and so falls the more certainly with any place
intended.
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knowledge of the Variation of the Compassed
yea besides the particular knowledge of Places,
the expert Navigator stand in great hope hereby
to attain unto good help for the finding of
Longitudes
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Exact truth amongst the constant waves of the sea
is not to bee looked for, though good instruments
bee never so well applied Causes of error
herein, some cannot be avoided, as the
unsteadiness of the ship, the imperfection of
sense instruments, the weak respective force of
the needle or wires, be they never so well
touched. Others may be eschewed, as that there
be no iron near the Compass in time of
observation
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in the place where Sir Thomas Button did winter
in 57 degrees of latitude, the constant great
tides every twelve hours, and the increase of
those tides whensoever any strong western wind
did blow, doe strongly persuade us that the main
Western Ocean is not far from thence which was
much confirmed onto them the summer following
when sailing directly North from that place where
they wintered, about the latitude of 60 degrees,
they were crossed by a strong Currant running,
sometimes Eastward, sometimes Westward So that
wee may assure our selves that from thence we
may with great ease pass to any part of the East
Indies.
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the Cape of California, which is now found to be
an island
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I have observed that some of our masters take a
wise course, in not trusting to those courses
which are showed by their charts. But first
getting themselves into the height or parallel of
the place to which they are going and withal,
knowing assuredly whether they be more eastward
or westward than that place they then proceed
always heedfully keeping themselves under that
parallel till they come to the place desired.
Then which way of sailing there is none indeed
more certain and infallible for the sure finding
of the place assigned.
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coming Mondays at One For those in peril on the
sea March 2006