ON PHYSICAL AND ENGINEERING FEATURES OF THE MERSEY, 559 
Soon after the author took charge as Engineer, it became evident that 
the days of sailing ships were numbered, trade and steam developing on 
all sides, so that ships of greater size, with increased speed and draught, 
became the ruling requirements to ensure successful trading. 
As a natural sequence, it was found that the older docks were rapidly 
becoming obsolete for this new class of ship, so that docks of improved 
type had to be specially designed and brought into use with all possible 
despatch. Fortunately the foresight of the Dock Board had provided for 
this contingency by the large enclosure—about 300 acres of foreshore—they 
had effected north of Canada Dock. -An area of about 80 acres at the 
southern end of the Estate also had for some years been waiting for 
development. 
These lands were handed over to the author in order to prepare 
designs for furnishing them in some form to meet the new conditions, the 
result being that the groups, north of Canada Basin, and known as the 
Alexandra system, at the North End, and the Herculaneum at the 
south, including the Harrington, Toxteth, and Union Docks, were carried 
out. 
The Parliamentary Estimates for the whole of these works amounted 
to 4,100,000/. The main features of these schemes, both north and south, 
were such as to afford ample and convenient accommodation for ships of 
the largest class, in view at the time of their design, with facility of 
ingress and egress to and from the docks, and approaches with entrances 
as deep as the conditions of the river would safely justify ; also abundant 
quay and water space, large shed accommodation, and all requisite 
appliances for the rapid discharge of goods, combined with wide roadways 
and convenient lines of railway in full connection with the main trunk 
lines of the country. Fortunately the large area of the enclosure at the 
north and the favourable condition of the river in the vicinity admitted 
of these desiderata being obtained. 
The northern scheme comprised the extension and alteration of the 
Canada Basin and its pierhead, with the lowering of the level of its 
floor ; the formation of the Langton Half-tide dock, which was to be the 
vestibule for the surrounding group ; two graving docks, each 950 feet 
long ; a branch dock for repairing purposes ; a great steam dock with 
three branches, called the Alexandra; and a dock opening out of it 
called the Hornby, being the northernmost dock on the Estate. The total 
water area of this group amounts to 83 acres, having an aggregate 
quayage of 23,700 lineal feet. The Parliamentary Estimates for this 
section of docks amounted to 2,691,360/., within which they have been 
completed. They were opened for traffic on September 8, 1881, by their 
Royal Highnesses the Prince and Princess of Wales. 
In designing works of this important character one of the difficult 
matters to successfully accomplish is that of effecting a simple and ready 
means of keeping the approaches, entrances, and dock sills clear of silt, 
with which the water of the Mersey is largely charged. This becomes all 
the more necessary where ships are large and valuable, and difficult where 
the sills are laid at abnormally low levels. 
In the case of this group the sills were laid at twelve feet below 
datum, being the deepest in the river with the exception of those pre- 
viously constructed at the northern entrances of the Birkenhead Docks. 
For the purpose of maintaining the required depth in the dock approaches 
a special arrangement of sluices of an elaborate character was designed. 
