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AS FAST AS HE CAN READ
Tap-tap-tap go the keys, and with each of tbe staccato sounds a letter flashes away to the operator's left, borne by
the metal vane.
THIRTY MAN-POWER POSTAL
SORTING MACHINE
By D. H. BACH
INSTALLED at the Chicago postoffice
is a new and striking machine
for distributing mail. It looks like
a monster typewriter attached to a
belt conveyor, and is the first mechanical
letter distributor to be adopted
by any post-office.
Since postal distribution was instituted,
there never has been any other
system for distributing letters but by
hand. A clerk stands in front of a
pigeonhole case and dockets the letters
according to the proper separation
scheme, or else before a rackful of open
sacks, pouching the letters or bundles of
letters by throwing them into the proper
receptacle. In practical post-office work
in large cities, all mail matter is divided
into twenty-eight "primary" separations,
each separation being then redistributed
a given number of times until the final
"direct" packet is made up. But the new
556
machine is changing all that; it is simplifying
the distribution process as much
as Whitney's cotton gin simplified the
cotton seed separation.
The post-office "tank" consists of a
key-board of 256 keys, which control a
sort of switch-track of four little rails.
Above these little rails and beside the
key-board, travels an endless belt, on
which are set upright at regular intervals
large flat metal receptacles, open at
the ends near the key-board. These receptacles
look like huge envelopes with
one end open. Projecting from the bottom
of each receptacle are four small
rods, each of which can take four different
positions. Thus the combination
of four units, each of which has four
possible movements, gives a combination
of 256 possible positions.
The positions of these small rods are
determined by the position of the four