MR. (4. I. TAYLOi; ON TFDAL FRICTION TN TIIF IRISH SEA. 
•'ll 
Effect of the Ehcc}X' of the Coast in Determinhoj the 
on the Coast. 
Time if //. ir. at Points 
This is too coiii])licate(l a matter to treat quantitatively, there is, liowever, one 
point in connection with local peculiarities of tlie tides of the Scnith (Jljaiinel of the 
Irish Sea which can be explained qualitatively by the analysis contained in tins paper, 
and that is the effect of a point of land projecting into the channel in alteiTig the 
times of H. W. on the two sides of it. 
•Consider the effect of a ])oint of land on the range.(>f" tide due to a tidal wave 
passing along a channel. Let AB, fg. (4), represent a ])ortion of one side of a 
channel and let CDE be a ])oint of land projecting into it. 
Suppose the tidal wave moves along in the direction from A to R. At H. W. the 
tidal stream is moving from A to B, it might l)e ex])ected therefore that, owing to 
the piling up of the water on side facing the current, the level of the water would be 
higher at C than at E at H.W., that is to say, the range of tide should be greater 
Fig. 4. Effect of a cape on times of H.W. on either side of it. 
on the side of tlie cape wlucli faces the direction froin which the tidal wave comes 
than it would be on the side which faces away from the direction of tlie tidal ivave. 
This effect does not materially alter the time of H.W. when there is only one tidal 
wave in the channel. When, however, there are two nearly equal waves, one going 
up and the other going down, the case is altered. 
The time C of H.W. at distance x is given by 
cot 
T 
a — b 
a b 
cot 
27r,r 
ffr 
. 01 ) 
Suppose now, that, without altering .r, a is decreased while b is increased by the 
action of some local peculiarity'^^ as it is on the side IlE of the cape (fig. 4). 
If a: is positive and <— then equation (41) shows that a decrease in a and an 
cl 2 
increase in b will lead to an increase in t^., the time of H.W. 
* This increase must not be su great as to reverse the tides. 
