fficiently moderate for dock gates to be dispensed with, and
for open basins and river quays to serve for the accommodation of
vessels. For ports established on the sea-coast of tideless seas, such
as the Mediterranean, on account of the rivers being barred by deltas at
their outlets, like the Rhone and the Tiber, and thus rendered
inaccessible, open basins, provided with quays and protected by
breakwaters, furnish the necessary commercial requirements for sea-going
vessels, as for example at Marseilles (fig. 5), Genoa, Naples and
Trieste. These open basins, however, are precisely the same as closed
docks, except for the absence of dock gates, and the accommodation for
shipping at the quays round basins in river ports is so frequently
supplemented by river quays, that closed docks, open basins and river
quays are all naturally included in the general consideration of dock
works.

[Illustration: FIG. 1.--Liverpool Docks, North End]

[Illustration: FIG. 2.--Havre Docks and Outer Harbour.]

[Illustration: FIG. 3.--Glasgow Docks.]

[Illustration: FIG. 4.--Southampton Docks and River Quays.]

Sites for Docks.

Low-lying land adjoining a tidal river or estuary frequently provides
suitable sites for docks; for the position, being more or less inland,
is sheltered; the low level reduces the excavation required for forming
the docks, and enables the excavated materials to be utilized in raising
the ground at the sides for quays, and the river furnishes a sheltered
approach channel. Notable instances of these are the docks of the ports
of London, Liverpool, South Wales, Southampton, Hull, Belfast, St
Nazaire, Rotterdam, Antwerp and Hamburg. Sometimes docks are partially
formed on foreshores reclaimed from estuaries, as at Hull, Grimsby,
Cardiff, Liverpool, Leith and Havre; whilst at Bristol, a curved portion
of the river Avon was appropriated for a dock, and a straight cut made
for the river. By carrying docks across sharp bends of tidal rivers,
upper and lower entrances can be provided, thereby conveniently
separating the inland and sea-going traffic; and of this the London,
Surrey Commercial, West India, and Victoria and Albert docks are
examples on the Thames and Chatham dockyard on the Medway. Occasionally,
when a small tidal river has a shallow entrance, or an estuary exhibits
signs of silting up, docks alongside, formed on foreshores adjoining the
sea-coast, are provided with a sheltered entrance direct from the s