John Logie Baird (1888-1946)

MARCH 1928

TELEVISION

[NLS note: a graphic appears here – see image of page]

Seeing in Total Darkness by Television

    By RONALD F. TILTMAN, F.R.S.A., A.M.I.R.E., A.Rad.A.

                    Author of “Television for the Home,” “Wireless Without Worry,” etc.

IN the course of experiments con-
nected with the development of
his television apparatus, Mr. J. L.
Baird, the inventor of the “tele-
visor,” has produced one of the most
remarkable developments of modern
times. With the aid of what he aptly
calls “the noctovisor,” he has over-
come the powers of darkness and has
demonstrated the possibility of seeing
in total darkness, or fog, by means of
television.

The sensatíonal demonstrations of
this “noctovision,” which the in-
ventor gave in Leeds on the occasion
of the British Association meeting
early in September, will be well
remembered, for they were very
freely reported in the press. He gave
short distance tests from one room
to another in Leeds, and these
certainly excited the greatest in-
terest. In spite of admission being
restricted to ticket holders only, there
were continuous queues formed both
in the hope of obtaining tickets and
also to view the demonstrations.

    A Long-Distance Test.

In order to prove his assertion
that distance was no drawback, he
also gave several 170-mile tests,
people seated in the dark at Leeds
being seen as if under normal lighting
conditions on a receiving screen in
London.

On September 7th last Mr. Baird
arranged one of these amazing 170-
mile demonstrations. Two telephone
lines were used; over one came the
image of Lieut.-Colonel J. R. Yelf, a
member of the British Association,
and over the other I conversed with
the inventor, asking for various
movements of the head and hand to
be made while I watched the results
on the screen.

For this demonstration I entered
a darkened room on the top floor
of a building near Leicester Square.
Before me was a large cabinet, near
the top left-hand corner of which
was inset a panel of frosted glass,
roughly a foot square.

There was a humming sound as
the apparatus was awakened to life,
and then a smear of orange light
appeared behind this glass panel,
whirling from top to bottom. In
this light, as synchronising adjust-
ments of the apparatus were made,
the flickering image of a face appeared.
The image was about 2 inches square
and outlined in black lines. At times
it was remarkably clear, although, of
course, by no means perfect, but
occasionally it became obscured by
black lines which oscillated across the
image.

It was positively uncanny—like a
page from the Arabian Nights tales—
to sit in London and watch this
swaying reproduction of the living
face of a person who sat in complete
darkness nearly two hundred miles
away. A face which, in obedience to
telephoned requests, turned, opened
its mouth, and made other move-
ments.

          The Infra-red Ray.

This mastery over darkness is made
possible by the use of what are
known as infra-red rays; these, being
outside the visible spectrum, cannot
be seen with the human eye.

The spectrum is, of course, divided
up into sections. Working down-
wards we come firstly to gamma rays
as given off by radium, then X-rays,
ultra-violet rays, the visible part of
the spectrum we know as light,
infra-red rays, and, lowest of all,
wireless waves. To the human eye
the only visible part of the spectrum
is that which lies between the colours
of violet and red.

After his first demonstrations of
television, when the subject who is
being “televised” had to face a
powerful battery of blinding lamps
which nearly scorched the skin, the
inventor decided that it was essential
to reduce the amount of illumination
required before his apparatus would
be commercially successful.

After some months of research
he was able to demonstrate television,
using no more than normal lighting
power from a few ordinary electric
lamps.

In view of this success, he next
decided to continue his experiments,
having in mind what appeared to be
the fantastical idea of dispensing
with light altogether, for he remem-
bered that he was not dealing with
the human eve in his tests but the

                        40