AN

ELEMENTARY TREATISE

ON

PLANE & SPHERICAL TRIGONOMETRY,

WITH THEIR APPLICATIONS TO

NAVIGATION, SURVEYING, HEIGHTS AND DISTANCES,
AND SPHERICAL ASTRONOMY,

AND PARTICULARLY ADAPTED TO EXPLAINING THE

CONSTRUCTION OF BOWDITCH'S NAVIGATOR, AND THE

NAUTICAL ALMANAC.

BY BENJAMIN PEIRCE, A. M.,

Perkins Professor of Astronomy and Mathematics in Harvard University.

THIRD EDITION, WITH ADDITIONS.

BOSTON:

JAMES MUNROE AND COMPANY.

M DCCC XLV.

Entered according to act of Congress, in the year 1845, by
JAMES MUNROE AND COMPANY,

in the Clerk's Office of the District Court of the District of Massachusetts.

Thurston, Torry, & Company, Printers,
31 Devonshire Street, Boston.

CONTENTS.

PLANE TRIGONOMETRY.

CHAP.

I. General Principles of Plane Trigonometry

II. Sines, Tangents, and Secants

III. Right Triangles

IV. General Formulas

V. Values of the Sines, Cosines, Tangents, Cotangents,

Secants, and Cosecants of certain Angles

37

97

. 104

IV. Middle Latitude Sailing

V. Mercator's Sailing