me exposition of
their distinguishing technical features. Several of these systems are
at present in practical and very effective operation.

One of the forerunners of the printing telegraph systems now in use
was the Buckingham system, for many years employed by the Western
Union Telegraph Company, but now for some time obsolete. The receiving
mechanism of this system printed the messages on telegraph blanks
placed upon a cylinder of just the right circumference to accommodate
two telegraph blanks. The blanks were arranged in pairs, rolled into
the form of a tube and placed around the cylinder. When two messages
had been written a new pair of blanks had to be substituted. This was
a rather awkward arrangement, but at a time when more highly developed
apparatus had not been perfected it served its purpose to good
advantage.

The printing telegraphs of to-day produce their messages by the
direct operation of typewriting machines or mechanisms operating
substantially in the same manner as the ordinary typewriting machine.
The methods by which the electrical impulses coming over the line are
transformed into mechanical operation of the typewriter keys, or what
corresponds to the typewriter keys, vary. It would be difficult to
describe how this function is performed without entering upon much
detail of a highly technical character. Suffice it to say that means
have been devised by which each combination of electrical impulses
coming over the line wire causes a channel to be opened for the motor
operation of the typewriting key-bar operating the corresponding
letter upon the typewriter apparatus. These machines write the
messages with proper arrangement of the date line, address, text, and
signature, operating not only the type, but also the carriage shift
and the line spacing as required. A further step in advance has
been made by feeding the blanks into the receiving typewriter from
a continuous roll, an attendant tearing the messages off as they are
completed. The entire operation is automatic from beginning to end and
capable of considerable speed.

There remained the problem of devising some means by which a number of
automatic units could be operated over the same line at the same
time. This is not by any means a new proposition. Here again various
solutions have been offered by the scientists both of Europe and of
this country, and different systems designed to accomplish the desired
object have been placed in ope