The description of a new, easy, and accurate method of adjusting the back observation glass : of Wright's improved patent octant, and the method of using it in taking the apparent altitude of the sun at sea and measuring angular distance from 0 to 180 [de
MLA
Wright, Gabriel, and mathematical instrument maker. The Description of a New, Easy, and Accurate Method of Adjusting the Back Observation Glass : of Wright's Improved Patent Octant, and the Method of Using It in Taking the Apparent Altitude of the Sun at Sea and Measuring Angular Distance from 0 to 180 [De. s.n., 0AD. https://collections.library.yale.edu/catalog/10186899.
APA, 6th edition
Wright, G., & mathematical instrument maker. (0 C.E.). The description of a new, easy, and accurate method of adjusting the back observation glass : of Wright's improved patent octant, and the method of using it in taking the apparent altitude of the sun at sea and measuring angular distance from 0 to 180 [de [Engravings, Illustrations, Instructions (Document genre), Pamphlets]. s.n., https://collections.library.yale.edu/catalog/10186899.
