Good morning Bill,
The compass is a Burt Astronomical Compass invented by
William Austin Burt in 1855 or thereabouts.
Burt described its function and use in some detail.
Burt, William A. (1881) A key to the solar compass, and
surveyor's companion; comprising all the rules necessary for use
in the field. Also, description of the linear surveys, and
public land system of the United States; notes on the barometer,
suggestions for an outfit for a survey of four months, etc.,
etc. New York, D. Van Nostrand. 5th edition. (Facsimile reprint
by Carben Surveying Reprints)
There is also some more information in his biography
Burt, John S. 1985 They left their mark. William Austin Burt
and his sons, surveyors of the public domain. Landmark
Enterprises, Rancho Cordova.
The "Key to the solar compass" is available as a free
download from Internet Archive (a wonderful source of all sorts
of old books and journals). Different editions are at the
following URLs
Cheers, John
In cold, overcast and rainy Sydney. Where has spring gone?
----- Original Message -----
Sent: Thursday, November
04, 2010 1:04 PM
Subject: Mechanically
Complex Solar Compass on sale at auction
I saw (on-line) this interesting sun compass for sale by auction
this coming November 20th. I have not seen anything like it.
Other scientific instruments, clocks, sundials for sale at same
auction. I doubt I will bid on it.
-Bill
http://www.skinnerinc.com/asp/fullcatalogue.asp?salelot=2527M++++363+&refno=++874110
Lot 363
Brass Solar Compass by W. & L. E. Gurley, Troy, New
York, the brass instrument with Burt's solar attachment,
horizontal circle read by opposing verniers, blued steel
needle and scale calibrated 0-15 in two segments and engraved
W. & L. E. Gurley, Troy, NY, silvered vertical half
circle arc graduated to 30 minutes with vernier scale and
sighting mounts, silvered declination and hour calibrated
arcs, dual spirit levels, graduated sighting vanes and thumb
screw leveling tripod attachment, ht. 14 in.
Estimate $2,000-4,000
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