PREFACE. 



constitution of matter. The second volume will 

 include subjects connected with geology, and the 

 third will be chiefly concerned with phenomena 

 of the ocean and maritime affairs. 



The lectures are reprinted practically in the 

 form in which they originally appeared, the only 

 alterations being slight verbal changes introduced 

 in a few cases solely for the sake of clearness. 



WILLIAM THOMSON. 



THE UNIVERSITY, GLASGOW. 

 Dec. 21, 1888. 



