224 Wisconsin Academy of Sciences, Arts and Letters. 



into a nearly ^^niform^J contracting channel, increases rapidly in 

 range as it ascends the Severn. Entering with range of 20 feet it 

 increases to 27 at Ilfracombe, to 35 at Bridgewater Bay, to 37 at 

 Cardiff, 88 at Chepstow and to 40 feet at Bristol. Above Bristol 

 the entire rise occurs in about two hours, and the fall in about ten. 

 Here the resistance of friction is such that the axis of the wave is 

 much inclined by the dragging of the front, and the impulse from 

 the momentum of the volume. The front of the wave becomes 

 steeper and the rear slope much longer, the latter being drawn 

 to supply the next wave. 



The Mascarret Eager or Ba7^re is an exaggerated distortion due 

 to excessive contraction either lateral or vertical. The immediate 

 cause of this phenomenon is, that a sufficient quantity of water to 

 preserve the form of the wave is unable to rise in front before it 

 is overwhelmed by the heaped up water of the wave whose axis 

 is inclined so far from the vertical that it breaks over and rolls 

 along upon the surface. When occasioned by excessive lateral 

 contraction, the eager forms at and follows along the shores of the 

 stream, but when caused by shoals in the middle grounds it forms 

 and follows up the middle of the stream, preserving its identity 

 for a considerable time after passing the cause of the abnormity. 

 A few short waves generally follow the eager, leaving high water 

 immediately behind them. 



While investigating the various phases of the tidal phenomena, 

 it must be noticed that there always has been a determination to 

 have the tide move with the moon from east to west, and owing 

 to this desire many aspects have remained unnoticed, or have been 

 disregarded because they happened to conflict with some theory 

 under construction. In nearly all articles on tides the common 

 remark is, that " in tidal rivers the tide always moves up-stream, 

 even when this is in the opposite direction to that in which the 

 moon appears to move." This would imply that tide should re- 

 main under the moon while the earth revolved to the east, and 

 that the tides on the east shores are produced by the advance of 

 the solid earth against the suspended mobile waters. It is true, 

 the tide moves south along the east shores of Scotland and Eng- 

 land, but, as we have seen, it is also true that at the same time 



