Vlll PBEFACE. 



outlined reproductions of a few of them prepared by 

 Mrs. Blackburn herself as illustrations for this book. 

 They are literally bits out of the past, each contain- 

 ing an exact representation, by a most accurate 

 observer and clever draughtswoman, of some incident 

 which had just happened when the sketch was made. 

 The figures, even as outlined, bring back the persons 

 with singular vividness to the memory of those who 

 knew them. 



For these and many other advantages the thanks 

 of the authors are due to Maxwell's relatives, but 

 above all to his widow, not only for the free access 

 she has given them to various documents, such as 

 those mentioned above, but for the generous confid- 

 ence she has reposed in them throughout, and for 

 many important suggestions made by her during the 

 progress of the work. 



Their thanks are also due in an especial manner 

 to Professor G. G. Stokes of Cambridge for his kind- 

 ness in reading most of Part II. in MS., and for many 

 valuable suggestions both with regard to the subject 

 matter and the mode of treating it, which were re- 

 ceived from him ; and to Professor P. G. Tait of the 

 University of Edinburgh for his zealous and able 

 assistance in many ways. 



The book owes much, of course, to those who 

 entrusted the letters here published to the authors' 

 care. Their names are duly mentioned in the course 

 of the work. Our task has also been lightened by 

 the help of those friends whose contributions are 

 inserted with their names. In describing the life of 



