360 WAVES OF THE SEA 



visible diverging disturbance is not the outer edge 

 of the bow-waves, but the first interference band 

 of these and the stern-waves. On the approach 

 of the vessel to Gunten on her way from Spiez 

 I have noticed individual curved bow-waves come 

 into view beyond the straight line which had 

 formed the visible boundary at a greater distance. 

 On examining the line of the inner boundary of 

 diverging disturbance with the field-glasses I have 

 seen it as a band, skew-barred by the individual 

 diverging waves. These, I presume, are the rear 

 members of the stern-waves, which ought to 

 extend within the limits of the bow-waves. They 

 here make a somewhat small angle with the ship's 

 course and are consequently much crowded, with 

 a very small wave-length. 



I have never detected any rearward boundary- 

 line to the system of transverse waves, nor have 

 I seen light or dark bands indicative of interference 

 between those originating from the fore -part and 

 after -part of the ship respectively. 



Ship -waves, which maintain their form un- 

 changed and keep the same positions relatively 

 to the moving agent which produces them, 

 are classed as stationary or standing waves. A 

 curious progressive condition is, however, seen 

 among them when two steamers pass one another 



