500 POPULAR LECTURES AND ADDRESSES. 



sized duck has a splendidly shaped body for de- 

 veloping a wave-pattern, and going at good speed 

 it produces on the surface of a pond very nearly 

 the exact pattern of ocean waves. A little duck- 

 ling going as fast as it can, perhaps about a knot 

 an hour, shows very admirably the capillary 

 waves, 1 differing manifestly from the ocean waves 

 formed in the front and at the rear of a larger 

 body moving more rapidly through the open water. 

 I call attention to this, because, having given you 

 perhaps a rather dry statement of scientific facts, 

 if I can say a word that will lead you each to use 

 your eyes in looking at ships, boats, ducks, and 

 ducklings, moving on water at different speeds, 

 and to observe these beautiful phenomena of 

 waves, I think, even were you to remember nothing" 

 of this lecture, you would have something to keep 

 in your minds for the rest of your lives. 



1 For information regarding capillary waves, see Scott Russell's 

 Report on Waves (British Association, York, 1844, pp. 311-390) ; 

 also Parts III., IV., and V of Sir William Thomson's paper, 

 "Hydro-Kinetic Solutions and Observations" (Philosophical 

 Magazine, November 1871). 



