ELEMENTS

OF

PLANE AND SPHERICAL

TRIGONOMETRY.

WITH

LOGARITHMIC AND OTHER MATHEMATICAL

TABLES

AND EXAMPLES OF THEIR USE AND HINTS ON THE ART OF

PREFACE.

THE distinctive features of the following work belong partly to the course of which it forms a part, and need but a brief statement.

I. The device by which mathematical teaching is to be most promoted is, the author conceives, to be found in the minute subdivision of subjects, and the drill of the student in the separate details before combining them into a whole. The system to which we are thus led is seen in the arrangement of Chapters I., II., and V.

II. By exercises in which the subject is taken up in a concrete form, the formation of mathematical conceptions is greatly facilitated. An application of this principle is seen in the cases where the student is exercised in finding the values of trigonometric functions by construction and measurement.

III. The problems for exercise are quite varied in their character, and are intended to test not only the student's knowledge of the usual methods of computation, but his ability to grasp them and trace them out in the numerous forms they may assume in practical applications.

IV. In the arrangement, strictly logical order has been subordinated to order of teaching. In accordance with this principle, all the simpler applications of the trigonometric functions have been disposed of before their complex relations.

V. The scope of the work is generally limited to the subjects and treatment necessary in the fullest course of mathematics usually taught in our colleges and technological schools. The concluding chapter of each part perhaps exceeds the limit thus