06-037. American, late 4th quarter 19th century, signed in script on the compass face "W. & L.E. Gurley, Troy, N.Y." and described in W. & L.E. Gurley's 1895 "A Manual of the Principal Instruments Used in American Engineering and Surveying" as follows:
"This is essentially a Vernier Compass with a telescope in place of the ordinary sight-vanes, this giving the Surveyor the means of taking long sights, either on a level or on hilly ground. The telescope can also be supplied with attachments, as shown, and elevels and angles of elevation and depression taken, as with the more expensive instruments. The telescope is eleven inches long and of fine quality. The compass circle is moved about its center by a pinion placed underneath the circular plate, and the declination of the needle is set off to single minutes upon a divided arc attached to the plate, as shown in the cut. There is also a clamp screw by which the circle is made fast... The levels are both above the plate, and are made adjustable by capstan head nuts at either end. The instrument is commonly used on a ball-spindle placed in a compass tripod..."
This rare Vernier Transit Compass by W. & L.E. Gurley is in very fine overall condition, showing virtually no evidence of use, missing only the telescope lens cap. The original 11 3/4" x 8" x 14 1/2" fitted mahogany case is worn, but is still fully serviceable.
