"Made and sold by Gregory and Wright (the patentees), mathematical instrument makers near the India House, Leadenhail Street"--p. 4., "Suppose ... the following observation were taken June 10, 1785"--P. 2., and Folded plate (20 x 30 cm.) loose, originally tipped in between p. 2-3.
Publisher:
s.n.,
Subject (Topic):
Astronomical instruments --Early works to 1800, Navigation --Early works to 1800, and Octants
