e compressed air chamber.
From this section the grain is discharged by an outlet pipe by the
agency of compressed air. A similar system was introduced by Messrs
Haviland & Farmer, who have, however, since abandoned it on account of
difficulties connected with the application of the blast, which was
found to abrade the grain rather severely, especially at the bends in
the pipes. An even greater objection was the delivery of dust with the
grain, which made it impossible for trimmers to remain in the hold while
the elevator was at work. Messrs Haviland and Farmer now work on the
suction system, in which they claim to have introduced several
improvements, notably in regard to the purification of the air between
the vacuum chamber and the exhaustors, and in devising a new automatic
air trap.

The first pneumatic suction elevator in Great Britain was erected at the
Millwall docks (London) under the Duckham patents. At Sulina, on the
Lower Danube, a pneumatic elevator erected on the Haviland-Farmer
system, which has undergone one or two reconstructions, has been proved
capable of elevating 160 tons of grain per hour with 375 i.h.p.

The only objection to pneumatic elevators appears to be that of expense.
The cost of installation is relatively heavy, and the power required for
working is large. But in dealing with vessels carrying heavy cargoes of
grain the saving of labour and demurrage is sufficient to justify the
large outlay of capital required in ports where there is sufficient
grain traffic.

_Hot Coke Conveyors._--Hot coke is admittedly one of the most difficult
materials to handle by mechanical means, and though it might be too much
to say that all difficulties have been surmounted by the engineer, it
has, since the end of the 19th century, been more or less satisfactorily
handled by machinery. Even in a dry state coke is a troublesome material
to handle by machinery. It is of a gritty and rasping nature, and is at
the same time very friable. Unless it is gently handled, breakage is
bound to occur and to result in the making of a certain proportion of
fine dust known as "breeze." Apart from the depreciation in the value of
the coke, this breeze is a sharp, cutting material, calculated to do
considerable injury to the working parts of the conveyor, such as
chains, and to the bearings, if it can get inside. Of course the
conveying of the coke in an incandescent condition is another serious
difficulty, as this glowing m