PREFACE
Advantage has been taken of the preparation of the third edition of this work to add a chapter on Ellipsoidal Harmonics and Lamé's Equation, and to rearrange the chapter on Trigonometrical Series so that the parts which are used in Applied Mathematics come at the beginning of the chapter. A number of minor errors have been corrected and we have endeavoured to make the references more complete.
Our thanks are due to Miss Wrinch for reading the greater part of the proofs and to the staff of the University Press for much courtesy and consideration during the progress of the printing.
E. T. W.
G. N. W.
July, 1920.
