﻿a Tidal Problem. 748 



The table gives results for a series of lengths varying from 

 to 5400 miles. The unit in terms of which the range is 

 expressed is the quantity H_, whose value for the lunar tide 

 is about 1*80 ft. The hour-angles <j> and </>i have been 

 adjusted so as to lie always between ±90°, and the positive 

 sign denotes position W. of the meridian in the case of the 

 eastern end of the canal, and E. of the meridian in the case 

 of the western end. 



The diagrams show successive forms of the wave-profile on 

 the dynamical theory in the case of 2a = 18°, corresponding 

 to a length of 1080 miles. In fig. 1 the curve a corresponds 



Fisr. 1. 



to the instant when the moon (or antimoon) is over the cen t re 

 of the canal, and the following curves />, c </, <\ / represent 

 the profile at intervals of one-twentieth of a period, or 36 

 minutes. Only one quarter of a complete cycle is shown ; 

 the remaining curves might be obtained by reflexions with 

 respect to vertical and horizontal axes through the centre. 



