gainst the wheel; and for moving the paper when a
fresh line is needed. These are too complicated to be described here in
detail. By means of relays one transmitter may be made to work five
hundred receivers. In London a single operator, controlling a keyboard
in the central dispatching office, causes typewritten messages to spell
themselves out simultaneously in machines distributed all over the
metropolis.

The tape machine resembles that just described in many details. The main
difference is that it prints on a continuous ribbon instead of on
sheets.

Automatic electric printers of some kind or other are to be found in
the vestibules of all the principal hotels and clubs of our large
cities, and in the offices of bankers, stockbrokers, and newspaper
editors. In London alone over 500 million words are printed by the
receivers in a year.

HIGH-SPEED TELEGRAPHY.

At certain seasons, or when important political events are taking place,
the telegraph service would become congested with news were there not
some means of transmitting messages at a much greater speed than is
possible by hand signalling. Fifty words a minute is about the limit
speed that a good operator can maintain. By means of Wheatstone's
_automatic transmitter_ the rate can be increased to 400 words per
minute. Paper ribbons are punched in special machines by a number of
clerks with a series of holes which by their position indicate a dot or
a dash. The ribbons are passed through a special transmitter, over
little electric brushes, which make contact through the holes with
surfaces connected to the line circuit. At the receiver end the message
is printed by a Morse inker.

It has been found possible to send several messages simultaneously over
a single line. To effect this a _distributer_ is used to put a number of
transmitters at one end of the line in communication with an equal
number of receivers at the other end, fed by a second distributer
keeping perfect time with the first. Instead of a signal coming as a
whole to any one instrument it arrives in little bits, but these follow
one another so closely as to be practically continuous. By working a
number of automatic transmitters through a distributer, a thousand words
or more per minute are easily dispatched over a single wire.

The Pollak Virag system employs a punched ribbon, and the receiver
traces out the message in alphabetical characters on a moving strip of
sensitized photographic pa