PREFACE. XIX 



succeeded in completely identifying himself with Cavendish's methods. He shewed that 

 Cavendish had really anticipated several of the discoveries in electrical science which have been 

 made since his time. Cavendish was the first to form the conception of and to measure 

 Electrostatic Capacity and Specific Inductive Capacity; he also anticipated Ohm's law. 



The Cavendish papers were no sooner disposed of than Maxwell set about preparing 

 a new edition of his work on Electricity and Magnetism; but unhappily in the summer 

 term of 1879 his health gave way. Hopes were however entertained that when he returned 

 to the bracing air of his country home he would soon recover. But he lingered through 

 the summer months with no signs of improvement and his spirits gradually sank. He was 

 finally informed by his old fellow-student, Professor Sanders, that he could not live more 

 than a few weeks. As a last resort he was brought back to Cambridge in October that he 

 might be under the charge of his favourite physician, Dr Paget*. Nothing however could 

 be done for his malady, and, after a painful illness, he died on the 5th of November, 1879, 

 in his 49th year. 



Maxwell was thus cut off in the prime of his powers, and at a time when the depart- 

 ments of science, which he had contributed so much to develop, were being every day 

 extended by fresh discoveries. His death was deplored as an irreparable loss to science and 

 to the University, in which his amiable disposition was as universally esteemed as his genius 

 was admired. 



It is not intended in this preface to enter at length into a discussion of 'the relation 

 which Maxwell's work bears historically to that of his predecessors, or to attempt to estimate 

 the effect which it has had on the scientific thought of the present day. In some of his 

 papers he has given more than usually copious references to the works of those by whom 

 he had been influenced; and in his later papers, especially those of a more popular nature 

 which appeared in the Encyclopedia Britannica, he has given full historical outlines of some 

 of the most prominent fields in which he laboured. Nor does it appear to the present 

 editor that the time has yet arrived when the quickening influence of Maxwell's mind on 

 modern scientific thought can be duly estimated. He therefore proposes to himself the duty 

 of recalling briefly, according to subjects, the most important speculations in which Maxwell 

 engaged. 



His works have been arranged as far as possible in chronological order but they fall 

 naturally under a few leading heads; and perhaps we shall not be far wrong if we place 

 first in importance his work in Electricity. 



His first paper on this subject bearing the title "On Faraday's Lines of Force" was 

 read before the Cambridge Philosophical Society on Dec. llth, 1855. He had been previously 

 attracted by Faraday's method of expressing electrical laws, and he here set before himself 

 the task of shewing that the ideas which had guided Faraday's researches were not incon- 

 sistent with the mathematical formulae in which Poisson and others had cast the laws of 



* Now Sir George Edward Paget, K.C.B. 



c2 



