THE IRISH AND ENGLISH CHANNELS. 
113 
cases, when the streams oppose, wholly overpowering" or reversing their direction, influence of 
That you may the more readily comprehend this explanation, I annex two charts, stream 
Plate IX. and X., upon which I have traced the course of the stream at alternate hours the channel, 
of a spring tide, each line representing the direction of the stream at the same moment Courses of 
throughout both channels. From the connection of the observations of the Irish Sea aiterna^e”^ 
with those of the Bristol Channel, it is clear that the whole of tiie ebb or outgoing hours of the 
stream of the eastern half of the Irish Channel runs into the Bristol Channel, and Dungeness 
forms the flood or ingoing tide of the northern half of that great estuary; and vice the Irish 
versa, the ebb or outgoing stream from the northern half of the Bristol Channel, 
forms the flood of the Irish Sea, each tide passing to and fro with great rapidity Bristol 
round St. Govan’s Head. The centre and southern half of the Bristol Channel Channel, 
receive their waters from the offing and the English Channel, the coast stream bring- 
ing the waters up from the Land’s End and the English Channel, as the stream on 
the northern half did those of the Irish Channel, and vice versa. 
The great offing stream at the entrance of the English Channel extends its influence Effect of the 
as far up as Cape La Hague, beyond whieh, owing perhaps to the sudden eontraction 
which there occurs in the Channel, the stream suffers no interruption, but, as in the tide in the 
Irish Sea, passes up and down the Channel six hours nearly each way as far as a 
line joining Dungeness and Cape Grisnez, the apparent virtual head of the tidal 
channel. Here the influence of the North Sea stream begins to be felt, and here, as 
in the Irish Channel, again the time of high and low water at the virtual head of the 
tide regulates the turn of the up and down stream along the whole channel as far as the 
contraction. Beyond this the offing stream being governed by its own high water, 
and that occurring at about six hours earlier than that of the head of the channel, 
the offing stream either butts against the returning streams from the channels, or 
withdrawing its water, solicits their streams and thus alters their course, making 
them for the most part set across the Channel in curves more or less bent as the spot 
is more or less removed from the offing ; so that there seems to be but one hour’s 
tide each way that passes clean down the Channel from Beachy Head to Scilly, and 
round the Land’s End to Bristol. The outgoing stream from Beachy Head en- Meeting of 
counters the ingoing stream of the offing tide somewhere about the Start Point, and streams, 
both are turned down into the great Gulf of St. Malo, which seems to receive the 
accumulated waters of these opposite tides. 
Whether or not this influx is instrumental in raising the water here to the extra- 
ordinary height of forty-seven feet perpendicular range at springs, or whether it be 
owing to its form and position as regards the advancing tide-wave, I leave to those 
who are competent to decide ; but it is a coincidence that cannot escape observation, 
that this spot, like the Bristol Channel, is the concentration of streams from opposite 
directions ; that it has its waters raised to the same extraordinary elevation nearly to 
a foot, and that its time of high water is nearly the same. 
On the change of tide, this great bay, like the Bristol Channel, as it received so it 
Q 
MDCCCXLVIII. 
