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I didn't see that particular TV programme about Thompson, but saw an earlier
one from the same presenter, Ray Mears, about Thompson's predecessor with
the Hudson's Bay Company, Samuel Hearne.

And it turned out rather like Geoffrey Kolbe's description of the later
broadcast. As is often the case, there was more about the presenter than
about the subject of the programme; Mears is a man interested in
survivalism, bushcraft, remote wilderness, so that was what we heard about,
rather than any surveying or navigational skills.

Certainly, the arts of living-off-the-land, and collaboration with the
native people, were necessary for the travels of those early surveyors. They
covered immense distances, on foot and by canoe, without military backup, to
survey the vast tracts of Canada. It was a long time before the geography of
what became the United States, to the South, would be mapped so well. In
comparison, the navigation of Lewis and Clark was quite inept.

Anyone interested in the work of those surveyors should take a look at two
recent papers by Peter Broughton, who has done much work on the astronomical
history of Canada.

"The Accuracy and Use of Sextants and Watches in Rupert's Land in the
1790s", in Annals of Science, vol 66 No 2, April 2009, 209-229

"Astronomical Observations by Peter Fidler and Others in "Canada"
1790-1820", in JRASC (Journal of the Royal Astronomical Society of Canada)
August 2009, pages 141-152.

In those papers are accounts of the work of Turnor, Thompson,  Fidler, who
in turn had surveyed the immense lands of the Hudson's Bay Company. Fidler
must have been a remarkable character, taken on as a labourer, with little
education, who learned on-the-job from Thompson.  He measured longitudes by
a variety of methods; solar and lunat eclipses, Moon occultations, Jupiter
satellites. I had never even heard of him.

There's rather a lot, there, about lunar observations for longitude, and
also about the precision available with instruments of that era, that may
listmember might find to be of great interest. I imagine that access won't
yet be available to those papers via the adsabs service (that usually seems
to take a couple of years), but I have found Peter to be a particularly
helpful character, and he may still be able to offer preprints. He is at
pbroughton@3web.net. (which might come over better as-
pbroughton-AT-3web.net  . )

An older paper of his can certainly be accessed online at -
http://articles.adsabs.harvard.edu/full/1981JRASC..75..175B

This is Title: Astronomy in 17TH-CENTURY Canada
Authors: Broughton, P.
Journal: ROYAL ASTRON. SOC. OF CANADA. JOURNAL V. 75, P. 175, 1981

Among many other topics, it details lunar observations made for longitude,
with varying success, made by Baffin and by James in Hudson's Bay, in the
early 1600s, long before lunar distances became available.

Surveying these new lands is an enormous topic, which has had little
attention on Navlist so far.

contact George Huxtable, at  george@hux.me.uk
or at +44 1865 820222 (from UK, 01865 820222)
or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13 5HX, UK.


----- Original Message -----
From: "Geoffrey Kolbe" 
To: 
Sent: Sunday, November 29, 2009 6:57 AM
Subject: Re: [NavList 10843] Thompson mapping Canada


| Frank wrote [NavList 10840]:
|
| >Here's a brief, interesting account of the life of David Thompson
| >who did a lot of mapping work in Canada starting around 1790
| >frequently using lunars to determine longitudes:
| >http://news.bbc.co.uk/2/hi/uk_news/wales/8354658.stm
| >
| >According to the article, there was a program on BBC television on
| >this last week. Anyone see it?
| >
| >-FER
|
| I watched it last night. (I uploaded it during the week using the BBC
| iplayer program). The programme was one of a series by Ray Mears, (a
| survival specialist who makes programmes about how to light fires in
| the wood and catch rabbits using home-made snares and so forth), who
| is 'doing' Canada from the backwoodsman outdoor-skills point of view.
|
| The photography is magnificent and worth watching for that alone.
| However, David Thompson is something of a hero to Ray Mears, so we
| get quite a bit about his history - how he was born in Wales (hence
| the Welsh connection in the link you found), but moved to London at
| an early age. He was a bright lad though and on leaving school at 14,
| was indentured to the Hudson Bay Company and left for Canada, where
| he went on to learn surveying skills and map a vast chunk of the
| Canadian hinterland. His greatest achievement was to find and map a
| route through the Rockies, so uniting West and East Canada. He never
| returned to England or Wales.
|
| As you might suspect though, there is not much on his surveying and
| navigation methods. We are introduced to the sextant, with close-ups
| of something that belongs to the end of the 20th century rather than
| the 18th. The covered pan of water as the artificial horizon is
| shown, and there are a few agonizing minutes where Mears attempts to
| find the altitude of the sun, searching for the direct image of the
| sun via the index mirror while looking at the reflected image of the
| pan of water. Then he hands the sextant to the 'expert' who is with
| him to demonstrate how it is done - and he cannot do it either! Mears
| announced solemnly that it is not easy and his respect for Thompson
| is greatly enhanced. And that is about it. No mention of Lunars, or
| time, or anything else.
|
| Geoffrey
|
| --
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| To , email NavList+@fer3.com

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