“Will you tell Mr. Mottelay that I shall feel honoured by his dedicating his “Chronological History of Electricity and Magnetism” to me, and express to him my thanks for his kind proposal to do so. “Yours very truly, “KELVIN.” I desire to record my great indebtedness to Dr. Silvanus P. Thompson, D.Sc., F.R.S., for the interest he has throughout manifested in, and the material aid he has given to, the improvement and development of the present work. Especial acknowledgment is made of Dr. Thompson’s personal revision of the articles on Petrus Peregrinus (at A.D. 1269), on William Gilbert (at A.D. 1600), and on Michael Faraday (at A.D. 1821). With all of these authors, he has become very prominently identified through the several special publications concerning them, which have been issued by him at different periods, and all of which are herein noticed in their proper order. Thanks are likewise due, and are also by me hereby tendered, more particularly to Dr. Elihu Thomson, of the Massachusetts Institute of Technology; to Dr. J. A. Fleming, M.A., F.R.S.; to Mr. W. D. Weaver, late Editor of the “Electrical World”; to Mr. Wm. J. Hammer, representative of Mr. Thomas A. Edison; to Mr. A. Hastings White, assistant-librarian, Royal Society, London; to Messrs. Charles Spon and Louis H. Walter, M.A.; to Messieurs Henri Omont, Bibliothèque Nationale; Paul Marais, Bibliothèque Mazarine; Henri Martin, Bibliothèque de l’Arsenal; Amédée Boinet, Bibliothèque Ste. Geneviève; Messieurs Plon Nourrit et Cie; as well as to Professors C. F. Brackett, William Hallock and Edward L. Nichols, of the Universities of Princeton, Columbia and Cornell; also to Sir Arthur Schuster, Sir Edwin Durning-Lawrence, Dr. Robert L. Mond, and Dr. Horace F. Parshall, for many valuable suggestions and other aid given by all of them at different periods to the material benefit of this compilation. It is scarcely necessary adding that, notwithstanding the great care given to the preparation of this very extensive Bibliography, and to its difficult “proof” reading, errors will undoubtedly present themselves. It is, however, hoped these will not prove of material importance. Such mistakes as are of a typographical nature can easily be recognized and in due time remedied; those, however, resulting from the conflict of authorities are more difficult to trace, and I shall greatly appreciate their being pointed out to me, with the view to improving future editions. P. FLEURY MOTTELAY. INTRODUCTION