, and communicates with the air compressor at the other end.
Compressed air can be admitted to the nozzle or shut off by a valve. The
inlet end of the flexible pipe is pushed into the grain in the barge,
while the other end is led over the hatches of the vessel to be loaded.
As the compressor is set to work and the valve of the compressed air
supply pipe opened, the air naturally rushes up the pipe and escapes at
the other end which is lying over the ship's hatchway. If the inlet
nozzle be immersed in the grain to the depth of 12 to 18 in. the induced
atmospheric air will follow the lead of the compressed air, and drawing
the grain around into the inlet nozzle will carry it up the pipe and
deliver it into the hold of the vessel loading.

[Illustration: FIG. 10.--Travelling Bucket Elevator.]

In the suction system, which is identified with the name of F. E.
Duckham, the process is somewhat different. An air-tight tank or
receiver, 8 to 10 ft. in diameter and 10 to 20 ft. high, is fitted with
a hopper bottom, and is erected, if floating, on a barge, at a
sufficient height to allow grain falling from the hopper bottom, and
passing through an air lock, to be delivered by gravity through a shoot
into the vessel being loaded. A pipe connects the vacuum tank with the
exhaust pumps. Several flexible pipes of sufficient length to reach any
corner of the ship to be unloaded, may be connected with the vacuum
tank. As the air pumps are set working a partial vacuum is formed within
the tank, and as the nozzle end of the pipe is immersed into the grain
to the depth of a few inches, the air and grain are drawn in at the
mouth of the nozzle and carried along the pipe to the vacuum tank. The
natural expansion of the air then lets the grain drop to the hopper
bottom, whence it issues from an air-lock valve, while the air is drawn
away by a pipe communicating with the pumps and is thence discharged
into the open.

In the third system, or blast and suction combined, the grain is sucked
into a vacuum tank, as just described, and drops from this through
valves into a second receptacle, whence it is conveyed to any desired
point by flexible pipes. This second tank is divided into two sections
and provided with valves so that the two sections will alternately be
under the influence of blast or suction. Alternatively the grain is
discharged by an automatic valve from the vacuum tank into the second
air-tight chamber which communicates with th