Evening star. [volume] (Washington, D.C.) 1854-1972, 1911-12-06
PICTURES BY WIRE
Progress Made in Sending
Photos by Telegraph.
SYSTEM USED IN LONDON
Daily Mirror Successfully Receives
Them From Paris-Still
in Infancy.
SYSTEM USED IN LONDON

| discussed for long time, but sufficient
| progress is being made in the art to in
dictate that before long It may be a sys-
| TEN In general use. This is the view
| taken by T. Thorne Baker. an associate
| Of the British Institute Of Electric En-
gineers. Mr.. Baker has been working on
the problem for years, and has written
an article on it's progress for the current
report Of the Smithsonian Institution.
| He says there are two possible systems
for accomplishing tho sending of pictures
by wire. The use Of silenium, he says,
\ is scientifically the most attractive and
| interesting, but a commoner mechanical
system Is the moro practical, and that is
the one now being employed. Silenium
| has the peculiar property Of changing its
electrical resistance with the amount Of
light thrown on 1t. This would seem the
natural solution Of the problem Of picture
telegraphy, but Mr.. Baker says as mat
ter of fact the old half-tone picture Is a
| more practical medium.
There Is another step now being made
with the invention, and that is in sending
pictures by wireless, and 1t is claimed
that this system Is within measurable
distance of the time when handwriting,
bank signatures and plans and pictures
can be transmitted across the Atlantic.
System Now in Use.
The process in use, Mr.. Baker says, has
been installed by the London Daily Mir
ror. and the pictures are received each
night In London from Paris and are
transmitted thence to Manchester for 81
multaneous publication. The system is
simple enough in theory. but intricate in
detail The picture to be sent is photo
graphed on a load foil flooded with fish
glue as a Photographic solution. There is
a hah-tone screen of about thousand
lines to the inch interposed. This of
course. breaks the picture up into minute
squares Of light and shade. The lead
foil picture is wrapped around sending
drum. and, of course, each Of the fish
glue lines acts as a little hillock to raise
a stylus that is run over the surface,
and this in turn interrupts an electric
current.
At the receiving end Of the line there is
a similar drum covered with absorbent
paper that has been soaked in a colorless
chemical solution. When there is an cleo
trio impulse sent through a stylus that
runs over its surface it turns the paper
dark. Thus as the stylus on the sending
end runs over it's cylinder the current is
made and broken, and as these impulses
come out at the receiving end they make
marks on the chemically prepared paper.
All this is simple enough, but there are
practical difficulties In the way The
electric impulses are sent at the rate OF
about 300 per second Electricity is very
quick, but 1t takes an appreciable time
for a wire to empty itself OF current once
1t has been filled up, just like water run
ming out of pipe. only much quicker.
So the electrician has to introduce into
the apparatus a. "shunt" that chops off
the current short and makes a sharp
ending contact instead Of one that dwin
dies down into a thin tail.
Other Difficulties Encountered.
Then there is the question of getting the
sending and receiving drums to run at
the same rate of speed. Carefully as
electric motors can be made. one will al
ways run little faster or slower than
the other. and If the sending motor over
hauled the receiving motor and got the
nose of the picture where the chin ought
to be. the result would be disastrous So
the motors are kept from varying by
very simple device. They each make a
revolution in about two seconds and in
this time with a pair of carefully bal
anced motors there is not time for one to
get much ahead of the other. But to
make sure the receiving motor is run just
shade faster than the sending motor
and when the cylinder gets at the end Of
its two-second revolution there is a catch
thrown in and the cylinder is stopped for
the infnitisemal part of second while
the other motor catches up. When 1t does
the electric current releases the catch
and the cyltndW continues to revolve.
This system has been SO satisfactory
that pictures are sent daily between Paris
and London and during the Steinheil trial
there were pictures of principals and wit
nesses received daily In London before
the court in Paris had finished its sitting
1t is pointed out by the author that the
cost Of maintaining a big sending and re-
ceiving station is considerable and may
easily amount to more than the pictures
are worth. He is therefore working on a
smaller sending set so that a photograph
er can be sent anywhere with his camera,
make his picture and hitch himself to a
telegraph wire and send the result into
the home Office.
It is pointed out also that plans and
sketches Of Notifications can be trans
mitted in the same way. Mr.. Baker says
the work as yet is in its very early stages
and that in a few years the public may
come to look on the methods now en-
ployed as crude and elementary in view
of the more wonderful things likely to be
| accomplished.