ee Ss ys 
THE SILTING UP OF THE DEE: ITS CAUSE. 57 
first hour after low water 2ft. 4in. per hour; in the second 
hour, 4ft. 8in.; third hour, 6ft. 3in. ; fourth hour, sft. gin. ; 
fifth hour, 2ft. gin.; in the last three-quarters of an hour, 3in. ; 
total rise, 22ft. Thus in the first two hours’ flow the tide rose 
7 feet, in the next two hours to 19 feet, and in the last hour and 
three-quarters to 22 feet, the total rise. This tide flowed at 
Hilbre for 5 hours and 45 minutes. In the third and fourth 
hours it flowed more than half the total rise. Now, what took 
place at Chester? The head or bore passed the Cheese-stage at 
10.23 a.m., when it was then nearly high water at Hilbre; the. 
tide at Chester flowed for an hour and forty-six minutes, and 
there was a total rise of the tide of 11ft. 6in. at Chester, giving 
the speed of about five miles per hour between Hilbre and 
Chester as the average rate of progress of the flood. 
Tue Tipe AT HILBRE. 
Does the tide come in or go out at Hilbre more quickly? It 
comes in more quickly than it goes out. I have the full 
particulars of the morning tide at Hilbre on April 7, 1875. 
The rise was as follows:—First hour, rise per hour 2ft. 8in. ; 
second hour, 6ft.; third hour, 8ft. 11in.; fourth hour, 7ft. 10in. ; 
fifth hour, 4ft. rin.; and last 20 minutes, 63in.; 5 hours 20 min., 
total rise 30ft. oin. How didit go out? First hour, fall per 
hour, 2ft. 43in.; second hour, sft. 3in.; third hour, 6ft. gin. ; 
fourth hour, 6ft. 9in.; fifth hour, s5ft.; sixth hour, 3ft. oin. ; 
last 40 minutes, low water, ift. 4in.; 6 hours 40 minutes, total 
fall 31ft. 23in. The tide at Hilbre, you will notice, comes in 
with its greatest strength during the third and fourth hours, 
and likewise goes out most quickly during the third and fourth 
hours of the ebb. For instance, the tide flowed 16ft. roin. in 
the third and fourth hours of the flood, and went out 13ft. 6in. 
during the third and fourth hours of its ebb ; there is a deficiency 
on the flowing out of the ebb of 3ft. 4in. in depth, as compared 
to the rate of rise of the greatest flow. While it took the whole 
tide only 5 hours 20 minutes to come in, on the other hand it 
took to go out 6 hours 40 minutes, or 1 hour 20 minutes longer 
on the ebb than the flood. What does all this mean? It 
means the silting up of our estuary slowly but surely. And 
here again the stupidity of man has conspired to hasten it by 
reclaiming the ‘‘ white sands,” or Sealand, and hence embank- 
ment after embankment, and so reducing the power of the scour 
of the returning tide in the estuary. The sediment which will 
come in on the flood, and part of which will remain on the ebb 
in our estuary for ever, is thrust forward; and as every new 
embankment is advancad towards the mouth, this deposit is also 
thrust forward. We need no better example of this than the 
rapid silting up along the shore from Burton Point to Parkgate 
within the last hundred years. 
