114 
CAPTAIN F. W. BEECHEY ON THE TIDES IN 
Gulf of St. 
Malo tide. 
Comparison 
of the tidal 
phenomena 
of the En- 
glish and 
Irish Chan- 
nels. 
returns its waters in opposite directions ; the tide splitting somewhere between 
Alderney and the Start. But here especially, as also in a similar locality in the 
Irish Channel, we are in want of observations, and it is very unfortunate that this 
spot, which from its peculiarity is the most interesting of any in the English Channel, 
should be so completely deficient ; for it seems most evident that the tidal streams 
meet off here, running together at one time and separating at another. 
Such appears to be the explanation of the complicated motion of the waters at the 
entrances of these two great channels, and of the course of the stream in the English 
Channel above the contraction of the strait. 
In tracing these streams, it was impossible not to be impressed with the many 
coincidences which assimilate the tidal phenomena of the two channels, so much so 
as to render it probable that they are subjected to precisely the same laws. As I 
feel confident that the consideration of this subject will be both interesting and 
useful, I shall endeavour to trace the resemblance through its several varieties. 
First, I shall consider the Irish Channel to extend, as above mentioned, from a 
line joining the Land’s End and Cape Clear to the end of the tidal flow, which is 
either at Morecombe Bay or Peel in the Isle of Man ; and the English Channel as 
reaching from a line connecting Ushant with the Land’s End, to the end of its tidal 
flow, or to Dungeness. We shall then see that the English Channel from its outer 
limit to the end of its tidal stream is 262 geographical miles, and that the Irish 
Channel from its western limit to the end of its tidal stream, is nearly the same, being 
about 265 geographical miles. In both channels the stream enters from the south- 
west, and flows up until stopped by a counter stream. In both channels there is a 
contraction of the strait almost midway, by the promontories of Cape La Hague in 
one instance, and St. David’s Head in the other, and at very nearly the same distances 
from the entrance. This contraction is, in both cases, the commencement of the 
regular stream, which flows six hours nearly each way, the turn of the stream through- 
out coinciding with the times of high and low water at the virtual head of the channel, 
situated in both cases about 145 miles above the contraction, and that time being 
very nearly the same, viz. 10^ 50'" at F and C*. Below this contraction, away from 
the land, the stream in both cases varies its direction nearly every hour, according to 
the force exerted upon it by the opposing offing stream. 
In both cases, between the contraction and the southern horn of the channel, there 
is situated a deep estuary, the Bristol Channel and the Bay of St. Malo, in which the 
times of high water coincide, and where, in both cases, the opposing streams meeting 
in the channel, pour their waters into these gulfs, and where the tides in both places 
rise to the extraordinary elevation of forty-seven feet at the syzygies. From the 
Land’s End to the meeting of these streams in the Bristol Channel is seventy-five 
miles, and from Brest to the meeting of the streams off Guernsey the same. A still 
further coincidence is apparent between the phenomena of these channels. In one, 
* See Plate XI. 
