The Washington bee., 1899-06-03
ARTIFICIAL DAYLIGHT
Nikola Teala's Discovery TO be Put to .
Practical Test.

Nikols Tesla's Discovery to be Put to
Practical Test.
The promise made by Nikola Tesla
to the world some two years ago that
he would soon give it means or light
ing it's homes, it's offices and its streets
at night time by artificial daylight
has been fulfilled. The invention has
been entirely completed for several
weeks. A day or two ago the author
itative announcement was made that
contracts have already been signed
with several New York business
houses to equip their business places
with the new light at once. The pro-
moters of the company which is push
ing the new invention are so certain
Of its great practical utility that they
predict that it must soon supplant the
arc lamp.
Vacuum tube lighting by high fire.
uuency currents" is what Tesla himself
calls it. The name. though clumsy. is
sufficiently descriptive. The essential
parts are a vacuum tube, and special
current of high frequency, produced by
a special dynamo, of Tesla's invention.
"The tubes" Mr.. Tesla explains, have
had all the air pumped out. but, OF
course, are full OF ether. The passage
of this special current sets the ether in
motion, forming light waves. The light
differs from arc illumination in that 1t
has no particular center. The whole
tube glows and sheds a radiance like
daylight all around"
The tubes, of course, are sealed tight
at both ends A wire is made fast to
one end, but there is no wire inside.
The tubes at present in use are about
a foot long. For special purposes. such
as studio illumination. street lighting
and so on, they can be made any size
UP to yard The glory and the beau
ty of them is that their light goes all
over the place to be illuminated-is as
strong in the corner of room, as di-
rectly under the tube. Hence the truth
of it's name, artificial daylight. A
lighted tube in a room has exactly the
effect of daylight flooding the win
dows. Notwithstanding the tube itself
is not trying to the eyes. You may
look steadily at it, with no evil effects
whatever.
In incandescent lighting 81 per cent
of the electric current goes to making
the filament hot, leaving but per
cent. for illumination. And this brings
us to a second long advantage of the
vacuum tube. 1t never grows hot. You
may touch the glass an hour after the
light is turned on and find it as cool
as when first lighted. An electric
bulb in like case is hot enough to
scorch. not to mention giving head
- 70 W n
pen to sit directly underneath or be-
side it.
The tubes can be attached to the cleo
trio light fixtures in common use, but
cannot be Illuminated by the ordinary
current Or rather they can be made
to glow with it, but the process is too
costly. That was one thing that made
the wise men doubtful in the beginning.
A few of them thought Tesla might
probably perfect his light process, but
were firm in the belief that it would
remain too costly for commercial use.
Tesla's new dynamo has changed all
that. Contracts now signed insure that
several important structures in New
York city will be equipped with the
new light. There can be no doubt
that it will rapidly supplant other
methods of illumination as soon as
moneyed men build and operate high
frequency current stations. The first
cost of wires, tubes. etc. is about the
same as for incandescent lighting, but
the tubes have the very great virtue OF
not burning out after the manner OF
incandescent globes or carbon pencils,
hence the cost of operation will be very
much less.
When it comes to use there is simply
no comparison possible. 1t is just the
same as having a day twenty-four
hours long. Everywhere, for every
purpose. artificial daylight equals the
real thing. The photograph of the in
ventor's hand was made at midnight,
in his laboratory, with two-second
exposure. 1t was not only taken, bue
printed by the artificial daylight, yet
it shows clearly the lines of the palm
and the texture of cuff and sleeve.
Nothing remains now but to equip
the world with proper wires, dynamos,
and so on. Men with money know d
good thing when they see it, even
without artificial daylight, so it is very
likely that in matter of twelve
months there will be practically no
night in any considerable city OF the
world.