PREFACE. 



IT is with much diffidence that I submit this Memoir to the 

 public. It was undertaken partly as a duty to the memory of 

 my father, partly in the belief that it would not be unacceptable 

 to the many readers of his different works. His pursuits, indeed, 

 were so earnest and various, and his writings extended over such 

 a wide range of subjects, that some account, however imperfect, 

 of his doings, and some selection, however incomplete, from his 

 writings, could not, I felt, be without interest to the general 

 reader. 



I was further desirous to bring under public notice a record 

 of my father's inventions and researches, especially in that 

 branch of science to which he first gave the name of Electro- 

 Metallurgy. His treatise on this subject, which went through 

 several editions, has long been out of print. From it has been 

 taken the introductory chapter on the history of Electro-Metal- 

 lurgy, included in the present selection. 



I have devoted considerable space, also, to the enunciation 

 and discussion of my father's views on Mental Philosophy, and 

 have extracted several passages from ' The Mind of Man/ his 

 last work on this his favourite subject, and the last published 

 work of his life. 



The numerous scientific papers, lectures, pamphlets, anony- 

 mous and other writings of my father have also furnished con- 

 tributions to the present volume. Artists will find something 

 to interest them in his remarks on binocular vision, and on the 

 methods resorted to by various eminent painters to produce 



