DUBLIN UNIVERSITY PRESS SERIES. A HISTORY OF THE THEORIES OF AETHER AND ELECTRICITY FKOM THE AGE OF DESCAKTES TO THE CLOSE OF THE NINETEENTH CENTURY. BY E. T. WH1TTAKER, Hon. Sc.D. (DubL}; I.E.S.; RoyatAstronomer ofIreland. LONGMANS, GREEN, AND CO., 39 PATERNOSTER ROW, LONDON, NEW YORK, BOMBAY, AND CALCUTTA. HODGES, FIGGIS, & CO., LTD., DUBLIN. 1910. MM* DUBLIN: PRINTED AT UHE UNIVERSITY PRESS, BY PONSONBY AND OIBRS. THE author desires to record his gratitude to Mr. W. W. EOUSE BALL, Fellow of Trinity College, Cambridge, and to Professor W. McF. ORR, F.R.S., of the Royal College of Science for Ireland; these friends have read the proof-sheets, and have made many helpful suggestions and criticisms. Thanks are also'due to the BOARD OF TRINITY COLLEGE, DUBLIN, for the financial assistance which made possible the publication of the work. 236360