The Cook County herald. [volume] (Grand Marais, Minn.) 1893-1909, 1898-05-28
This very sensitive characteristic Of Sc

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This very sensitive characteristic OF se-
1enium is taken advantage Of to trans
nit pictures by wire. The dots Of
light, which really form the image TOT
be transmitted, are allowed to play
through a narrow slit in the partition
against the selenium cell in the top Of
the box. The selenium is part Of the
circuit or wire through which the pic
ture is to be transmitted. This circuit
may, for all practical purposes be
hundreds Of miles long. An electric
current is made to flow through it,
and, consequ emily, through the seleni-#
ums Now the reflection Of the man
outside the box, with all the colors Of
the costume, is being projected con-
stantly against the selenium in the top
of the box, and this rapid interchange
of color is causing the electric current
which flows through the selenium to
vary constantly in strength as the diff
ferent colors in the reflection affect the
resistance of the selenium. It there
fore follows that an electric current is
easily obtained, the strength of which
depends entirely on the nature of the
color which is projected against the Sc
lenium. The transmission of colors,
or at least the transmission Of their
equivalentsin electric currents, is what
has been accomplished.
Having accomplished the feat Of
sending colors, or their equivalents, by
telegraph, it now became necessary to
separate the various parts or intensi-
ties of this varying current, and to re-
solve them into colors again at the
| other end of the line. In short, just
as the selenium was able to change
| colors into their equivalents in current,
popularity speaking, so must some
/ method be found of changing these
currents back into their equivalent col
ors. 1t was done in the following man
ner: The line which transmitted all of
these varying currents ended in the re-
! ceiver in a coil which formed an cleo
| tro-magnet When the selenium* al
Flowed heavy currents to flow over the
wire the electro-magnet became very
| powerful. When weak currents flowed
over the line the electromagnetic be-
came weak. In front Of the core of this
4 magnet a large prism was placed. II
hung in a horizontal position, and
moved on a pivot. Attached to it was
a piece of soft iron. This iron was
4 naturally affected by the magnet, anc
i caused the prism to move backward OF
j forward as strong or weak currents
j flowed from the selenium at the Other
end OF the line.
It is q well known fact that if 1
4 strong beam of light is projected
through a prism the latter will separ
ate the various rays of that light an(
spread them out in the form Of spec
trum, or band of colored light. All
of the reds in the beam will be shoW1
at one end of the spectrum, all of tn,
blues at the other end, with the inter
mediate colors between. In the receiv
er of Szczepaniks apparatus power
full incandescent lamp was placed Jus
back of the prism, which moved on ;
pivot. Naturally, the prism took u,
the beam Of electric light and separated
it into a spectrum, or band of light
with the reds at one end of the ban(
and the blues at the other end. Thi
band of variously colored light shon
against partition in the upper part O
: the receiving apparatus. There was
narrow slit in this partition, cut S,
that only one color of the band of ligh
could shine through at a time. B,
moving the prism backward and for
ward it was easy to start at one en-
of the colored beam of light and max,
first the red lights shine through, ant
so on along the beam until the blue O
Violets were reached. 80 s.@e.35$
q Now, when the selenium in the frs
apparatus was affected by red light
q and a current corresponding il