300 WAVES OF THE SEA 



the gaze is thus fixed, the surface of the flowing 

 water has either a smoothed-out appearance or that 

 of stationary streaks or stripes. If, however, the 

 eye can be trained to follow the water in its flow, 

 it will be seen that its surface is usually covered 

 with travelling inequalities. This habit of vision 

 is somewhat difficult to acquire, and the movement 

 of the eye is always liable to be arrested involun- 

 tarily by some fixed object. If, however, a small 

 dead leaf, or a short piece of straw, or some such 

 light thing, be cast upon the stream, the eye follows 

 it in its drift naturally and with ease ; and then, 

 in shallow channels with a steep gradient, the 

 surface of the water, instead of having a smoothed- 

 out or striped look, is found to be covered with 

 rounded excrescences travelling at about the 

 speed of the stream. The smoothed surface is, 

 in fact, an optical illusion. An excellent oppor- 

 tunity of following up this observation was afforded 

 me by journeying up and down on the funicular 

 cars from Territet to Glion, and from Vevey to 

 Mont P61erin. The appearance of the water when 

 coming down (the car sometimes travelling at 

 almost exactly the speed of the current) was very 

 different from that when going up, or when standing 

 on the banks. On the Mont P61erin funicular, 

 when going up, the only surface inequalities visible 



