TRANSACTIONS OF SECTION G. 887 
The following comparative figures, kindly supplied by Mr. K. Miles Burton, 
may be of interest :— 
1871 1895 
Population of Liverpool. . . . 493,405 ., . 641,000 (Estimated) 
ra Birkenhead - . e 65,971 = ° 109,000 
” 
Area of docks, Liverpool, about . . 236 acres, 3624 acres 
s » Birkenhead, about . ° na - (aa 
383 5224 
Number of steamers using the port c 7,448 ° ° 18,429 
Average tonnage of six largest vessels 
entering the port ° - . ‘ 2,890 ° . 6,822 
The following figures show the importance of the local railway traffic :— 
Number of passenger stations within the 
boroughs : : - : “ — ¥ 58 
Number of goods stations. A F — H q 50 
Number of passengers crossing the Mer- 
sey in the twelve months (Woodside 
Ferry). ¢ : : : i 
Number of passengers crossing the Mer- 
sey in the twelve months (Mersey 
Railway) e . . . . . Tis . e 6,976,299 
° » 17,143,088 
To the hydraulic engineer there are few rivers of more interest, and present- 
ing more complicated problems, than the Mersey and its neighbours the 
Dee and the Ribble. They all possess vast areas of sand covered at high water 
but laid dry as the tide falls, and in each case the maintenance of equilibrium 
between the silting and scouring forces is of the greatest importance to the welfare 
of the trading communities upon their banks. The enclosure of portions of the 
areas of the respective estuaries for the purposes of the reclamation of land, or for 
railway or canal embankments, may thus have-far-reaching effects, diminishing the 
volume of the tidal flow and reducing the height of tide in the upper reaches of 
the rivers. Some idea of the magnitude of these considerations may be derived 
from the fact that a spring tide in the Mersey brings in through the narrows 
between Birkenhead and Liverpool 710 millions of cubic yards of water to form a 
scouring force upon the ebb. The tidal water is heavily laden with silt, which is 
deposited in the docks, and, at slack water, upon the sandbanks. The ‘former is 
removed by dredging, and amounts to some 1,100,000 cubic yards per annum ; 
the latter is gradually fretted down into the channels and carried out to sea before 
the ebb. Whilst a considerable portion of the narrows is kept scoured, in some 
places right down to the sandstone rock, there is a tendency, on the Liverpool side 
near the landing-stage, to silt up, a difficulty counteracted, to some extent by the 
extensive sluicing arrangements introduced by Mr. George Fosbery Lyster the 
engineer of the Mersey Docks and Harbour Board. ‘ 
Very extensive and interesting operations have been carried on by the Board 
in connection with the bar at the mouth of the river, Dredgers specially designed 
for the purpose have been employed for some six years, with the result that 
15,142,600 tons of sand and other dredged matter have been removed and the 
available depth of water at low-water increased from 11 to 24 feet in a channel 
1,500 feet in width. 
Those who have made the transatlantic passage in former years can more 
readily appreciate the very great advantage accruing from this great improvement 
Formerly vessels arriving off the port on a low tide had to wait for some hours 
for the water-level to rise sufficiently to enable them to cross the bar; the result of a 
large vessel lying outside, rolling in the trough of the sea with her engines stopped 
was that not infrequently this proved to be the worst part of the voyage ee 
New York and Liverpool, and passengers who had escaped the malady of sea- 
