452 POPULAR LECTURES AND ADDRESSES. 



waves of light and waves of sound, that they are 

 manifested at the surface or termination of the 

 medium or substance whose motion constitutes the 

 wave. It is with waves of water that we are con- 

 cerned to-night ; and of all the beautiful forms of 

 water waves that of Ship Waves is perhaps the 

 most beautiful, if we can compare the beauty of 

 such beautiful things. The subject of ship waves 

 is certainly one of the most interesting in mathe- 

 matical science. It possesses a special and in- 

 tense interest, partly from the difficulty of the 

 problem, and partly from the peculiar com- 

 plexity of the circumstances concerned in the 

 configuration of the waves. 



Canal Waves. I shall not at first speak of 

 that beautiful configuration or wave-pattern, which 

 I am going to describe a little later, seen in the 

 wake of a ship travelling through the open water 

 at sea ; but I shall as included in my special 

 subject of ship waves, refer in the first place to 

 waves in a canal, and to Scott Russell's splendid 

 researches on that subject, made about the year 

 1834 fifty-three years ago and communicated 



