PREFACE. Xxix 



treatise and its position relatively to his larger work may be gathered from the following 

 extract from Maxwell's preface. 



"In this smaller book I have endeavoured to present, in as compact a form as I 

 can, those phenomena which appear to throw light on the theory of electricity and to 

 use them, each in its place, for the development of electrical ideas in the mind of 

 the reader." 



"In the larger treatise I sometimes made use of methods which I do not think 

 the best in themselves, but without which the student cannot follow the investigations 

 of the founders of the Mathematical Theory of Electricity. I have since become more 

 convinced of the superiority of methods akin to those of Faraday, and have therefore 

 adopted them from the first." 



Of the "Electricity and Magnetism" it is difficult to predict the future, but there is 

 no doubt that since its publication it has given direction and colour to the study of 

 Electiical Science. It was the master's last word upon a subject t9 which he had devoted 

 several years of his life, and most of what he wrote found its proper place in the treatise. 

 Several of the chapters, notably those on Electromagnetism, are practically reproductions of 

 his memoirs in a modified or improved form. The treatise is also remarkable for the handling 

 of the mathematical details no less than for the exposition of physical principles, and is 

 enriched incidentally by chapters of much originality on mathematical subjects touched on 

 in the course of the work. Among these may be mentioned the dissertations on Spherical 

 Hannonics and Lagrange's Equations in Dynamics. 



The origin and growth of Maxwell's ideas and conceptions of electrical action, cul- 

 minating in his treatise where all these ideas are arranged in due connection, form an 

 interesting chapter not only in the history of an individual mind but in the history of 

 electrical science. The importance of Faraday's discoveries and speculations can hardly be 

 overrated in their influence on Maxwell, who tells us that before he began the study of 

 electricity he resolved to read none of the mathematics of the subject till he had first 

 mastered the "Experimental Researches." He was also at first under deep obligations to 

 the ideas contained in the exceedingly important papers of Sir W. Thomson on the analogy 

 between Heat-Conduction and Statical Electricity and on the Mathematical Theory of 

 Electricity in Equilibrium. In his subsequent efforts we must perceive in Maxwell, possessed 

 of Faraday's views and embued with his spirit, a vigorous intellect bringing to bear on a 

 subject still full of obscurity the steady light of patient thought and expending upon it 

 all the resources of a never failing ingenuity. 



ROYAL NAVAL COLLEGE, 

 GREENWICH, 



August, 1890. 



