The Jenkins duplex cylinder type of machine was designed for
simultaneously sending and receiving photograms, letters, maps,
drawings, etc. The motor runs all day long, like an electric fan, in
control of the vibrating fork. The right hand (glass) cylinder sends;
and the left hand cylinder receives. The messages are put on and taken
off without stopping the machine, and without one function interfering
with the other.
The machine may be used on radio or on wire, and is an easily operated
machine, the perfect functioning of which can be determined by a glance
at the perforated rotating disc illuminated by the synchronizing signal
lamp.
It is believed to be the first duplex two-way service machine ever
built, and is complete as shown, except for the batteries and the radio
receiving set, which latter may be any standard set which will operate a
loudspeaker.
The illustration shows a machine in which a picture transparency and a
sensitive cell is used at the sending cylinder; and a high speed lamp
and photographic paper at the receiving cylinder.
[Illustration: [Photographs]]
“Talking Machine” Photograms
The spring driven machine illustrated is probably the simplest device
possible for the experimental study of transmission of pictures and
picture messages by radio or by wire. A conducting ink or pencil line on
paper and put on one cylinder (or an insulating coating cut through with
a stylus) over which the sending point rides for sending; and an
electrolytic bromide (or photo) paper on the other cylinder under the
receiving pen for receiving; the contact points being attached to the
sending and the receiving sets respectively.
The upper illustration shows a machine electrically driven and equipped
to transmit and receive handwritings, maps, sketches, pictures, etc., of
an area of about 5 × 7 inches. The sending is from pencil lines on
paper, the reception on electrolytic paper.
The machine is also made with a glass cylinder to send from a picture
transparency, and to receive on photographic paper. It must, therefore,
be used in a dark or subdued lighted room to receive.
Each machine is capable of the very highest quality of work of its
particular kind, and is simple and easy to operate.
[Illustration: [Photographs]]