Gurley surveyor’s vernier compass, a pocket instrument for government land surveys

This surveyor's vernier compass was made by W. & L. E. Gurley of Troy, New York. Gurley described it as a most excellent and portable little instrument, especially useful to surveyors of government lands, and the record gives its price new as $21.

Surveyor's vernier compass, view 1.

How it reads

• The rim is graduated to 30 minutes.
• The right side of the face is graduated in degrees, numbered every 10 degrees from west to north and from west to south.
• The outside of the box carries a variation arc that extends 20 degrees either way and reads to 5 minutes by a folded vernier.

History and size

The U.S. Geological Survey, established in 1879, transferred this example to the Smithsonian in 1907. The record cites Gurley's A Manual of the Principal Instruments Used in American Engineering and Surveying (Troy, N.Y., 1878), page 138. The box is 6 in x 4 3/4 in x 4 7/8 in (15.24 cm x 12.065 cm x 12.3825 cm) and the needle 3 1/2 in (8.89 cm) long.

The object

Sources

• Smithsonian National Museum of American History, object record "Surveyor's Vernier Compass", object number PH.247917 (https://n2t.net/ark:/65665/ng49ca746a5-9ef5-704b-e053-15f76fa0b4fa), released under CC0 through Smithsonian Open Access; rewritten in hubnx's own words.