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> To summarise. Before devoting any attention to the longitudes, we have
> to understand why the latitudes are so wrong. In the meantime, an
> interim conclusion appears to be that Lewis and Clark were indeed
> hopelessly bad celestial navigators: the Emperors had no clothes. I
> bet that will stir things up. Anyone disagree?

Given that they let their watch run down at least twice, I would have to
agree that plotting their course was a low priority for them (despite the
emphasis that Jefferson placed on it in their instructions). Since they
would not have used any celestial observations for actually navigating
(local guides showed them which way to go all the way), perhaps they
felt that they only had to fulfil their duty to Jefferson in providing some
numbers, even if they were very poor. Since they had a good sextant
(two, I think) it seems quite strange that they were using a quadrant for
their noon altitude sighting.

Contemporary with Lewis & Clark, David Thompson and Peter Fidler
travelled about 90,000 miles throughout Canada (Thompson about
55,000 and Fidler about 35,000), taking celestial sightings throughout
their journeys (and they were expected to make a profit for the company
as well as indulging in their hobby of celestial navigation). Thompson's
map of the country West of the great lakes (which he completed upon
retiring from the fur trade) remained useful for almost a century without
improvements. Fidler's determinations were passed to Aaron Arrowsmith
every year for inclusion in his map of North America. On this score
Thompson & Fidler seem to be head and shoulders above L&C.

Ken Muldrew

   

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