This octant was made in America during the Revolution. It has a mahogany
frame and index arm, and ivory inset. The boxwood scale is graduated every 20
minutes from -5o to +95o and read by ivory vernier to
single minutes of arc. There is also a back sight and a back horizon mirror that
could be used to measure angles greater than 90o. There are faint
markings on the scale that may read "equality" and
"justice." Benjamin Condy (d. 1798) was in business in Philadelphia as
early as 1763, and several octants with his signature are known.
Ref: Deborah J. Warner, "American Octants and Sextants: The Early
Years," Rittenhouse 3 (1989): 86-112, on 93.
