PORT ECONOMICS
though logs are often stored in timber ponds until
required. Conveyors have been devised for the work of
unloading deals and planks, but they lack the discrimina-
tion of the human intelligence in regard to marks.
CARGO APPLIANCES

While it has been shown that the operations of dis-
charging and loading are very largely in private hands,
and although the port authority may not be directly
interested in such operations, yet it is universally recognized
that it devolves upon a port authority to equip its docks
and quays with adequate appliances for handling cargo.
These appliances are principally cranes, which are let on
hire on a time basis and may be engaged as desired. There
is no compulsion, or even necessity, to hire a port
authority’s quay cranes, when a ship is sufficiently equipped
(as indeed most are) with its own booms, whips and
tackle. But quay cranes are a useful appendage, and can
be used in conjunction with the ship’s equipment and also
to supplement it.

As the most outstanding port appliance for cargo
handling purposes, the Quay Crane merits some brief
notice. It has certain special features which differentiate
it from the ordinary type of land crane. On account of
having to clear the lofty bulwarks of a vessel in the light,
or unloaded, condition, and also for the purpose of
enabling the crane driver to command a view of his work,
it is generally mounted on a pedestal, which takes the form
of a framed substructure, mounted on a wheel base, and
designed to allow of the passage of railway stock between
its side supports and under its platform. The crane arm,
or jib, has generally a considerable outreach in order to
enable it to plumb the hold of a vessel which may have a
barge lying between the vessel and the quay. And, in
order to avoid collision with the yards and stays of shipping,
the jib is fitted with a luffing motion, which enables it to be
moved forward and backward in a straight line, in addition

H2