AND OTHER WATER WAVES 249 



away to the east of a sand-bank called the Wave- 

 ridge, or Waif ridge. After working thus to its 

 right until 4.30 p.m., with slow current but rapidly 

 rising level, the flood tide, having filled the swatch- 

 way brim full, suddenly swept over the Waifridge 

 Sand in a broad sheet of water, which poured over 

 to the westward into the main channel. 



The sands, which had been drying for several 

 hours, were covered so suddenly that the im- 

 prisoned air spouted through the seething water. 



It is evident that the presence of an alternative 

 channel, open from below, prevented the forma- 

 tion of a bore in this case, just as at Hock Cliff 

 the alternative channel, open from above, reduced 

 the bore after it had been formed. 



The flood tide goes the way of least resistance, 

 and if it be free to circulate, it does not stem the 

 ebbing stream and form a bore. The presence of 

 alternative channels, which becomes more marked 

 as we travel down-stream from Severn Bridge to 

 Sheperdine Sands, is in itself sufficient to explain 

 the non -format ion' of a permanent bore in the lower 

 portion of the steep slope of the estuary. 



Near Beachly Point, just below the foot of the 

 steep slope to which I have so frequently referred, 

 I watched the commencement of a spring tide on 

 April 28, 1900. The first rise was perfectly 



