PREFACE. 



Of the reason why Volume III. appeared before 

 Volume II. nothing need be said here, as it was 

 stated in the Preface to Volume III. 



The first half of the present volume contains 

 the papers relating to geological subjects referred 

 to in that statement. The remainder of the 

 volume consists of lectures and addresses on 

 various subjects of general physics, given between 

 1866 and the end of 1893, which have not been 



included in Vols. I. or III. 



KELVIN. 



UNIVERSITY, GLASGOW. 

 February 2, 1894. 



