Plane and Spherical Trigonometry

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. In the second method all lines have direction as well as magnitude, and the proofs are given in such a form that they are general and hold for every possible figure. This would seem to be the logical method of developing the subject; for Trigonometry is the connecting link between elementary Geometry and those subjects in which Algebra and Geometry are combined in such a way that the directed line must be used constantly. This second method has been employed in this work, which is in tended as a text-book for a fifty hour course in high schools and the ordinary first year classes in college, and is, therefore, made as elementary as possible. All matter not required for such a course has been excluded.