A description of an accurate and simple method of adjusting Hadley's quadrant for the back observation. By Mr. Robert Blair. Published by order of the Committee of Longitude.

[London : Peter Elmsly, 1788]

20,[4]p.,plate ; 80.

ESTC T112545

Electronic reproduction. Farmington Hills, Mich. : Thomson Gale, 2003. (Eighteenth century collections online). Available via the World Wide Web. Access limited by licensing agreements.