NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Sun compass
From: Michael Dorl
Date: 2007 Apr 12, 07:29 -0500
Although somewhat off topic, I thought some of you might be interested in the following.
The upper midwest portion of the USA especially northern Wisconsin, Minnesota, the Michigan Upper Peninsula (the part north of Wisconsin and south of Lake Superior) contains considerable deposits of iron. If one looks at modern maps of these areas showing political divisions, it looks like the surveyors must have been a bit tipsy. It turns out the section lines in these areas were set by magnetic compass, the standard surveying instrument in the early 1800s. I've even heard that these maps were used in later times to locate significant iron deposits by their effect on the compass instruments.
The latest issue of the 'Wisconsin magazine of history' contains a picture of a Sun compass. Use of this instrument allowed the surveyor knowing his latitude, time, and declination of the Sun, to determine true North. The instrument was developed and patented by one William Austin Burt in 1835.
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To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
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From: Michael Dorl
Date: 2007 Apr 12, 07:29 -0500
Although somewhat off topic, I thought some of you might be interested in the following.
The upper midwest portion of the USA especially northern Wisconsin, Minnesota, the Michigan Upper Peninsula (the part north of Wisconsin and south of Lake Superior) contains considerable deposits of iron. If one looks at modern maps of these areas showing political divisions, it looks like the surveyors must have been a bit tipsy. It turns out the section lines in these areas were set by magnetic compass, the standard surveying instrument in the early 1800s. I've even heard that these maps were used in later times to locate significant iron deposits by their effect on the compass instruments.
The latest issue of the 'Wisconsin magazine of history' contains a picture of a Sun compass. Use of this instrument allowed the surveyor knowing his latitude, time, and declination of the Sun, to determine true North. The instrument was developed and patented by one William Austin Burt in 1835.
--~--~---------~--~----~------------~-------~--~----~
To post to this group, send email to NavList@fer3.com
To , send email to NavList-@fer3.com
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