carry out this aim in such a manner that students may not be repelled by any unnecessary prominence of symbolic methods, and yet that the treatment may have all the exactness and precision in statement and deduction which the subject demands. This is a large ambition and I cannot hope to have been wholly successful, but I shall be grateful if my attempt is found in any degree to have subserved its purpose. My grateful acknowledgments are due to Dr. G. S. Fulcher of the University of Wisconsin, who has read nearly all the manuscript with great care, and to whom I am indebted for important suggestions, and to my colleague Professor J. O. Thompson whose criticism at all stages of the work and painstaking correction of the proof has been most helpful. AMHERST, March, 1911. A. L. K. |