cable. The power absorbed is not great, the heaviest
demand on the motive force being made by the elevating operation. Such
conveyors have the merit of handling the material gently, while feeding
and discharging can take place at any point. There are many journals to
be looked after, but in the most approved systems their lubrication is
effected automatically. Whilst such a plant has the advantage of
requiring only one driving gear, a breakdown at one point of the
installation means the stoppage of the whole.

Among typical conveyors on this system is the Hunt conveyor (fig. 10),
which consists of a double link carrying a series of pivoted buckets
which are free to revolve on their axes at all points, except at that
point at which they discharge. This operation is effected by a cam
action, the buckets on their release righting themselves and becoming
ready for refilling. The driving gear propels the chain by means of
pawls which engage with the cross studs of the chain and have a
central thrusting action. Another well-known appliance of this type is
the pan bucket conveyor. This consists of a continuous trough built in
sections and supported on axles and guide wheels running on suitable
rails. There is one axle to each section, and in each section of the
trough a bucket is pivoted to the sides. There are several other
conveyors of this type, amongst which the "Tipit" should be mentioned.
For the Bousse gravity conveyor it is claimed that it will go round
any curve backwards or forwards in both planes, and is therefore
adaptable for installations when the typical gravity bucket would be
useless. The buckets of this conveyor are coupled together by a link
in the middle, which obviously allows more latitude in negotiating
curves than the double chain of most of the other types.

_Pneumatic Grain Elevators_ have been employed with good effect in
loading and unloading grain from ships. This method of conveying grain
falls under three systems: (1) the blast system; (2) the suction system;
and (3) the combined blast and suction system.

In the first system a barge, known as a machinery barge, is fitted with
a steam boiler, a set of air compressing engines, and a length of
flexible piping long enough to reach from any part of the barge to the
farthest corner of the ship to be loaded. A small pipe, known as the
nozzle, is inserted at the inlet end of the piping, where the grain is
taken in