346 WAVES OF THE SEA 



The ranging of the water-cones in roughly trans- 

 verse bands is due to this cause ; they gradually 

 lose their transversality as they descend. 



Below a waterfall near Matt en, Grindelwald, the 

 waters flow steeply over a bed of rock, which gives 

 a uniform, small depth to the stream, which flows 

 in roll-waves owing largely to the initially dis- 

 continuous character of the motion of the falling 

 water. 



Below one of the principal leaps of the Giessbach 

 Falls (Lake of Brienz) I also saw down-stream 

 waves, which, however, soon lost their transver- 

 sality on entering the swift channel of exit from the 

 pool. 



When any waterfall or cascade discharges into 

 still, deep water, progressive trochoidal waves pro- 

 ceed outwards in all directions, as may be prettily 

 seen, for instance, in the ornamental waters of the 

 public gardens at Buxton. 



On the Wave -track of a Ship as seen on the Swiss 



Lakes 



The late Lord Kelvin described l the dual system 

 of waves which originates at the bow of a ship. 

 They are the diverging series, the fronts of which 

 1 " Popular- Lectures^and Addresses." 



