hope to express it more happily than does Mr. J. J. Fahie in the preface to his "History of Wireless Telegraphy, 1838-1899"; or, might adopt the words of two of the most learned French authors of the day: "Si je donne ces détails, nouveaux, ou peu connus, c'est qu'il est toujours intéressant de remonter à l'origine et au développement successif des inventions." (M. Berthelot, in the "Comptes Rendus.") "S'il n'y a pas beaucoup de gens qu'elles intéressent, il y en a qu'elles intéressent beaucoup. À ceux-ci, nous avons, en rédigeant ces notes, eu l'intention et l'espérance de venir quelquefois. en aide. Tout catalogue a des points obscurs, même les meilleurs. ... L'office propre, le devoir de la critique, est de rechercher si ces points obscurs ne pourraient pas être éclairés par quelque lumière. Il est vrai qu'elle y perd souvent sa peine. Mais cela ne doît jamais la décourager." (M. Hauréau, in "Le Journal des Savants.") I am especially thankful for the warm encouragement which I have received, on all sides, since the original work appeared in serial form. This History has been frequently called for, and I regret that I have been hitherto prevented from bringing it out earlier in its present desirable book form. This is the more to be regretted as it long ago received the practical endorsement of the doyen of the electrical profession, Lord Kelvin (formerly styled Sir William Thomson), to whom it is dedicated. Leave to do this was obtained through a mutual friend in such a cordial manner that I cannot refrain from giving the correspondence attaching thereto : Westminster Chambers, January 4, 1894. "DEAR MOTTELAY, "I duly received yours of the 21st . . . but the point on which I feel guilty is your dedication. . . . I have now started the matter by writing to Lord Kelvin fully on the subject, and I hope, within a week, to get his reply, which I shall at once send to you-he cannot possibly wish to decline the honour. . . . "I remain, "Yours very truly, "LATIMER CLARK." Westminster Chambers, London, S.W., "DEAR MOTTELAY, "Lord Kelvin's letter is so nice a one that I send you the original, otherwise I should have liked it as an autograph for my library. I shall be glad to hear that it has duly reached you. . "Yours very truly, "LATIMER CLARK," "DEAR CLARK, The University, Glasgow, January 11, 1894. "Your letter of the 4th should have been answered sooner, but for my absence from home at the time it came. "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 DurningLawrence, 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 ANYONE who enters on the perilous paths of Bibliography realizes, sooner or later, the truth that "of the making of books there is no end." But there was a beginning and if the Bibliography of Electricity promises to stretch onward into the future in endless line, at least its backward reach might seem to be finite in date. Nevertheless, the student of the early periods of book production, when the science of electricity was literally in that “infancy" from which in our time it has emerged, is continually finding that there are early works of which he was unaware, and of which even our best libraries are destitute. He finds, as he progresses backward, toward the origins of things, in how many points our ancestors in the domain of electric science had anticipated the discoveries of later date. He finds that, again and again, by some rare stroke of insight, the great minds that had devoted themselves to the research of phenomena had seen-it may be, with dim or imperfect glimpses-many of the things which are commonly regarded as quite modern. The pioneer, unbiased by the views of contemporary philosophers, unhampered by the load of textbook tradition, often sees further than the professed researcher who comes after him. The art of scientific discovery-for it is an art-can be attained in but one way, the way of attainment in all arts, namely, by practising it. In the practice of art, the aspirant may at least learn something that all the textbooks cannot drill out of him, and which will help him in his practice, by the careful examination of the actual ways in which the discoveries of science, now facts of history, were actually made. But, to do this, he must throw overboard for a time the systematic textbooks, he must abandon the logical expositions which embody, at second hand, or at third hand, the antecedent discoveries, and he must go to the original sources, the writings and records of the discoverers themselves, and learn from them how they set to work. The modern compendious handbooks in which the results of hundreds of workers have been boiled down, as it were, to a uniform consistency, is exactly the intellectual pabulum which he must eschew. Let him read Faraday, not through the eyes of Maxwell or of Tyndall, but in his own words in the immortal pages of the "Experimental Researches," with their wealth of petty detail and their apparent vagueness of speculation. Let him read Ohm's own account of the law of the circuit, not some modern watered-down version. Let him turn over the pages of Franklin's letters to Collinson, as his observations dropped red-hot out of the crucible of his endeavours. Let him read Stephen Gray's charming experiments in the old-world diction that befitted a pensioner of the Charterhouse. Let him go back to old Gilbert, who had talked with Drake and Sir Walter Raleigh in the flesh, who had discussed magnetism with Fra Paolo Sarpi and had experimented on the dip of the needle with Robert Norman. Gilbert's account of his own experiments is for the would-be scientific discoverer worth a hundredfold the Novum Organon of the overpraised Francis Bacon. Nay, let him go back to Peter Peregrinus, the soldier-pioneer, and see how he experimented with floating lodestones before he penned his account of the pivoted magnet-the earliest known instrument that can rightly be called a mariner's compass. Not until he has thus become a bit of an antiquary will be have fully understood how the discoveries of old were made. And, in precisely the same spirit of quest, though with the wealth of modern appliances at his command, must he go to work, if new discoveries are to be made by him. But, for all this, he needs a guide to tell him what are the records of the original pioneers, by what names their works are called, and where they can be found. Such a guide doubtless exists to some extent in the mere catalogues of electrical literature, such as the catalogue of the Ronalds' Library at the Institution of Electrical Engineers, in London; or, more fully, even, in the new Catalogue of the Latimer Clark Library, now known as the Wheeler Collection, at the American Institute of Electrical Engineers, in New York. The Chronological History of Electricity which Mr. P. F. Mottelay contributed, week by week, to the columns of the "Electrical World” and of "Engineering" in the years 1891-1892, was the beginning of an attempt to provide an even more complete analysis of the earlier literature of the subject. But these are only the beginnings. In the "Bibliographical History of Electricity and Magnetism,” which Mr. Mottelay is now giving to the world, a far more exhaustive and detailed account is rendered of the earlier workers and writers in our dual science. He has particularly worked up all important electrical channels, and in the more extended articles, some of which it has been the writer's privilege to peruse in advance, there are presented valuable monographs dealing with particular workers who each in his own day made notable contributions to the advance of the science. To all who would tread in their paths, and add something to the |