PREFACE. 



In the first few years at Cambridge Maxwell was busy in giving the final touches 

 to his great work on Electricity and Magnetism and in passing it through the press. 

 This work was published in 1873, and it seems to have occupied the most of his attention 

 for the two previous years, as the few papers published by him during that period relate 

 chiefly to subjects forming part of the contents. After this publication his contributions to 

 scientific journals became more numerous, those on the Dynamical Theory of Oases being 

 perhaps the most important. He also wrote a great many short articles and reviews 

 which made their appearance in Nature and the Encyclopaedia Britannica. Some of these 

 essays are charming expositions of scientific subjects, some are general criticisms of the 

 works of contemporary writers and others are brief and appreciative biographies of fellow 

 workers in the same fields of research. 



An undertaking in which he was long engaged and which, though it proved exceedingly 

 interesting, entailed much labour, was the editing of the "Electrical Researches" of the Hon. 

 Henry Cavendish. This work, published in 1879, has had the effect of increasing the 

 reputation of Cavendish, disclosing as it does the unsuspected advances which that acute 

 physicist had made in the Theory of Electricity, especially in the measurement of electrical 

 quantities. The work is enriched by a variety of valuable notes in which Cavendish's 

 views and results are examined by the light of modern theory and methods. Especially 

 valuable are the methods applied to the determination of the electrical capacities of con- 

 ductors and condensers, a subject in which Cavendish himself shewed considerable skill 

 both of a mathematical and experimental character. 



The importance of the task undertaken by Maxwell in connection with Cavendish's 

 papers will be understood from the following extract from his introduction to them. 



" It is somewhat difficult to account for the fact that though Cavendish had 

 prepared a complete description of his experiments on the charges of bodies, and had 

 even taken the trouble to write out a fair copy, and though all this seems to have 

 been done before 1774 and he continued to make experiments in Electricity till 1781 

 and lived on till 1810, he kept his manuscript by him and never published it." 



" Cavendish cared more for investigation than for publication. He would under- 

 take the most laborious researches in order to clear up a difficulty which no one 

 but himself could appreciate or was even aware of, and we cannot doubt that the 

 result of his enquiries, when successful, gave him a certain degree of satisfaction. 

 But it did not excite in him that desire to communicate the discovery to others 

 which in the case of ordinary men of science, generally ensures the publication of 

 their results. How completely these researches of Cavendish remained unknown to 

 other men of science is shewn by the external history of electricity." 



It will probably be thought a matter of some difficulty to place oneself in th.- 

 I position of a physicist of a century ago and to ascertain the exact bearing of hi< 

 l experiments. But Maxwell entered upon this undertaking with the utmost enthusiasm and 



