reason I have also tried to present the results in such a light as will make them effective tools for the student in his future work.
During the preparation and printing of the book, Prof. J. M. Peirce has kindly given me the benefit of numerous suggestions and criticisms, which have added greatly to its value. Appendix I. is entirely due to him.
Most of the examples contained in the book have been selected from other trigonometries, especially those of Todhunter, Snowball, and Hamblin Smith.
CAMBRIDGE, MASS., Dec. 3, 1876.