ly wrote the
message upon sensitized paper, like a pencil, in a fair handwriting.
In another the receiving apparatus printed vertical, horizontal, and
slanting lines in such manner that they combined to make letters,
rather angular, it is true, but legible.

These and other kindred devices are interesting as efforts to
accomplish the direct production of legible messages. In experimental
tests they performed their function successfully, and in some cases
with considerable speed, but some of them required more than one line
wire, some were too sensitive to disturbance by inductive currents
and some developed other weaknesses which have prevented their
incorporation in the actual operating machinery of to-day.

In the general development of the so-called automatic telegraph
devices which have been or now are in practical operation, two lines
have been pursued. One involves direct keyboard transmission; the
other, the use at the sending end of a perforated tape capable of
being run through a transmitting machine at high speed. One type of
the former is the so-called step-by-step process, in which a revolving
body in the transmitting apparatus, as, for instance, a cylinder
provided with pegs placed at intervals around its circumference in
spiral fashion, is arrested by the depression of the keys of the
keyboard in such a way that a type wheel in the receiving apparatus
at the distant end of the line prints the corresponding letter.
This method was employed in the House and Phelps printing telegraphs
operated by the Western Union Telegraph Company in its earlier days,
and is to-day used in the operation of the familiar ticker. In
another type of direct keyboard operation the manipulation of the
keys transmits the impulses directly to the line and the receiving
apparatus translates them by electrically controlled mechanical
devices into printed characters in message form.

The systems best adapted to rapid telegraph work are predicated on the
use of a perforated tape on which, by means of a suitable perforating
apparatus, little round holes are produced in various groupings, each
group, when the tape is passed through the transmitter, causing a
certain combination of electrical impulses to pass over the wire.
The transmitter as a rule consists of a mechanically or motor driven
mechanism which causes the telegraph impulses to be transmitted to the
line, and the combination and character of the impulses are determined
by th