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The solar compass.

In 1834, Michigan deputy surveyor William Austin Burt was subdividing land in the Lake Superior region when he ran into a problem. The needle on his magnetic compass, instead of pointing north, was swinging wildly, making it difficult to plot his survey lines.

Burt knew why it was happening: He had found iron ore in the area, which compromised his compass readings. The only way to locate true north was at night, using the North Star. During the day, surveyors had to rely on calculations that determined how far the magnetic compass was "off." With needles pointing every direction but north, that wasn't much help.

Burt had studied solar navigation, and he had a solution: Discard the magnetic compass altogether and take direction from the sun, whose location could be predicted with pinpoint accuracy. Burt's new device worked via three arcs--one for latitude, one for the declination of the sun (found via astrological tables), and one for local time. When a set of sights was pointed at the sun and the arcs were adjusted, a mechanically linked pair of pointers would align to true north.

Burt had a working model of his invention created by America's leading instrument maker, William J. Young of Philadelphia, then patented it on February 25,1836. It was cutting-edge technology, and solved a major problem for surveyors in mineral-rich areas like the Upper Peninsula, as its precision remained unaffected by ore deposits.

Burt employed the solar compass to settle a border dispute between Michigan and Wisconsin and to survey the U.P. Soon, the instrument (and its descendants) became the industry requirement, being used on every U.S. land survey from 1855 until the rise of global positioning system (GPS) devices. It's not a stretch to say that this Michigan-made invention charted the American West.

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Title Annotation:Made in MICHIGAN
Publication:Michigan History Magazine
Article Type:Brief article
Geographic Code:1U3MI
Date:Jul 1, 2016
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