The description and use, of a new constructed octant, sextant and quintant. By His Majesty's patent, being an improvement on the Hadley's quadrant. By either of which, altitudes are taken, and angular distances measured to the greatest precision from 0. to 160ʻ. Without a back observation, and with double the space of illumination, or field of view: also a new meth[o]d of adjusting the glasses, and applying the instrument for the purposes of finding the latitude and longitude at sea.. By G. Wright.

Date:

[1779?]