ON SHIP WAVES. 



[Lecture delivered at the Conversazione of the Institution of 

 Mechanical Engineers in the Science and Art Museum, 

 Edinburgh, on Wednesday evening, yd August, 1887.] 



" WAVES " is a very comprehensive word. It 

 comprehends waves of water, waves of light, waves 

 of sound, and waves of solid matter such as are 

 experienced in earthquakes. It also comprehends 

 much more than these. " Waves " may be de- 

 fined generally as a progression through matter of 

 a state of motion. The distinction between the 

 progress of matter from one place to another, and 

 the progress of a wave from one place to another 

 through matter, is well illustrated by the very 

 largest examples of waves that we have largest 

 in one dimension, smallest in another waves of 

 light, waves which extend from the remotest star, 



