extension arm is pivoted at B. Hence, as the armature is alternately
attracted when current passes around its electromagnet, and drawn up by
the spring on cessation of current, it moves up and down, thus actuating
the escapement and causing a rotation of the toothed wheel in the
direction of the arrow. This, in turn, brings any desired letters
or figures on the type-wheels to a central point, where they may be
impressed upon the paper tape. One type-wheel carries letters, and the
other one figures. These two wheels are mounted rigidly on a sleeve
carried by the wheel-shaft. As it is desired to print from only one
type-wheel at a time, it becomes necessary to shift them back and forth
from time to time, in order to bring the desired characters in line
with the paper tape. This is accomplished through the movements of a
three-arm rocking-lever attached to the wheel-sleeve at the end of
the shaft. This lever is actuated through the agency of two small pins
carried by an arm projecting from the press-lever, PL. As the latter
moves up and down the pins play upon the under side of the lower arm of
the rocking-lever, thus canting it and pushing the type-wheels to
the right or left, as the case may be. The operation of shifting the
type-wheels will be given further on.

The press-lever is actuated by the press-magnet. From the diagram
it will be seen that the armature of the latter has a long, pivoted
extension arm, or platen, trough-like in shape, in which the paper tape
runs. It has already been noted that the object of the press-lever is
to press this tape against that character of the type-wheel centrally
located above it at the moment. It will at once be perceived that this
action takes place when current flows through the electromagnet and its
armature is attracted downward, the platen again dropping away from the
type-wheel as the armature is released upon cessation of current. The
paper "feed" is shown at the end of the press-lever, and consists of
a push "dog," or pawl, which operates to urge the paper forward as the
press-lever descends.

The worm-gear which appears in the diagram on the shaft, near the
toothed wheel, forms part of the unison stop above referred to, but this
device is not shown in full, in order to avoid unnecessary complications
of the drawing.

At the right-hand side of the diagram (Fig. 2) is shown a portion of
the transmitting apparatus at a central office. Generally speaking,
this consists o