Elements of Plane Trigonometry Properties and Relations of Trigonometrical Lines Application of Trigonometry, &c. Solution of Oblique-angled Spherical Triangles Numerical Solution of Right-angled Triangles 39X6771 CORRECTIONS. The reader is desired to make the following corrections before he begins to read the book. After l. 17 add of the bottom, and CAE 51° Add the theorems in the last four articles are For s. 1'= read s. 1'+ For 2 read 1o After IV add and VI. 37 8 b. For 82 read 83. For 84 read 85. After the second of add the sine of Add Plate, fig. 4. Articles which may be omitted. The following articles may be omitted, or deferred till the second reading of the book. Art. 46, 47, 63 to 66, 75, latter part of 86 beginning at line 10, page 37, 88 to the end of Plane Trigonometry. Spherical Trigonometry, art. 50 to 57, 59 to 97, 103 to 120, 127, Ex. 4, page 119. of the best Mathematical and Philosophical Books FOR THE USE OF STUDENTS. FREND'S Algebra, 8vo. Ludlam's Rudiments of Mathematics, by Fryer, 8vo. English Translation of Euler's Algebra, 2 vols. 8vo. These four are the best books of algebra for beginners. Wood's Algebra, 8vo. This is the best elementary treatise of algebra for those who intend to study the higher parts of mathematics, but is too concisely written. Simpson's Mathematical Exercises, 8vo. Webber's Mathematics, 2 vols. 8vo. This is extracted, with improvements, from the best English books, and contains Arithmetic, Algebra, Mensuration, Navigation, Conic Sections, &c. Playfair's Elements of Geometry, 8vo. This is a new edition of Euclid's Elements, corrected, enlarged, and greatly improved. Legendre's Elements of Geometry and Trigonometry, 8vo, in French. Trigonometry, 8vo, published by Nichols. Kelly's Spherics, 8vo. Horsley's Mathematics, 8vo, vol. iii, containing the different Projections of the Sphere, the Elements of Trigonometry, &c. Robertson's Conic Sections, 8vo. The Conic Sections in Hutton's or Webber's Mathematics. Bonnycastle's Mensuration, 12mo. Hutton's Mensuration, 8vo. Vince's Fluxions, 8vo. Wood's Mechanics, 8vo. Vince's Hydrostatics, 8vo. Mackay's Navigation, 8vo. Bowditch's do. 8vo. Hutton's Mathematical Tables, 8vo. Mackay's do. 8vo. Brown's do. 8vo. Abridgment of Vince's Astronomy, 8vo. Fit only for adepts in mathematics. vi Young's Analysis of Natural Philosophy, 8vo. The following books may be read by persons who have little mathematical knowledge. Compend of Astronomy, 12mo, published by Nichols. Ferguson's do. 8vo. Biot's Elements of Physical Astronomy, 2 vols. 8vo, in French. Elements of Art and Science, by Webster, 2 vols. 8vo. Ferguson's Lectures on Select Subjects, by Brewster, 2 vols. 8vo. Adams's Lectures on Natural and Experimental Philosophy, by Patterson, 4 vols. 8vo.. Gregory's Dictionary of Arts and Sciences, 2 vols. 4to. Note. Many of the books toward the end of the list treat of the same subjects, and the last two comprise short treatises on the various branches of mathematics, natural and experimental philosophy, the useful and ornamental arts, &c. PREFACE. TRIGONOMETRY is a branch of the general science of geometry. It treats of the properties and relations of certain straight lines described in and about a circle, and also teaches to compute the dimensions of the sides and angles of any triangle. It supplies fundamental rules for ascertaining the distances and altitudes of objects both terrestrial and celestial. Without the aid of this science, the form and magnitude of the earth, and the magnitudes, distances, motions, and eclipses of the heavenly bodies would be utterly unknown. In geography, navigation, astronomy, and the military art, its assistance is absolutely necessary. By its unerring rules we are able to determine the latitudes and longitudes of places upon the surface of the earth, and the varying positions and appearances of the heavenly bodies; to survey countries, and to travel by sea or land to any part of the world, that is accessible to the adventurous spirit of curiosity or avarice. One main object of the publisher is to furnish a treatise of trigonometry, plane and spherical, of a middle size between the concise elementary tracts containing the definitions and a few theorems barely necessary to the solution of the common cases of triangles, and the larger and more comprehensive works, designed for the use of mathematicians, or of students who have time, ability, and inclination to enter deeply into such curious and difficult speculations. This treatise is the production of different authors of approved merit, whose shares may be nearly assigned as follows. Some articles have been supplied by Legendre, Horsley, and Lacroix, which, as they are not numerous, need not be specified. Plane trigonometry consists mostly of the lectures of an eminent mathematician, W. Ludlam, A. M., formerly a fellow and tutor of St. John's college, Cambridge. These, with |