The herald., 1893-05-09
LIGHT MINUS HEAT.
THE DISCOVERIES NIkoLA TESLA is
GIVING THE WORLD.

Electric Currents That Produce variegatesl
Streams Of Mysterious Light and Faii to
Heat the Wires That Carry These won-
| derful Currents.
Almost from the time that the vi1ra-
tory theory Of light was accepted scien-
tifc men have looked forward to the day
when it would be possible to produce
light without heat. For it is an unfor-
tunate fact that SO far every effort to
produce light has been accompanied by
an enormous waste Of energy due 10 the
production Of uselessheat. The simplest
way of producing light is by means Of
the combustion of some compound of
carbon. It does not matter whether the
carbon Is solid, as in candle, or fluid,
as in lamp, or in q gas, as in ordinary
illuminating gas, the process is the same.
The union Of the carbon of the SUBJ
stance with the oxygen Of the air pro-
duces the rapid vibration that the eye
recognizes as light Carbon, though the
element usually employed, is not aneces-
sary factor, for magnesium, potassium,
irori--indoed almost any Of the elements
will take it's place. Neither is oxygen
q necessary part in the production Of
light. Chlorine will produce an even
more brilliant light with certain sub
stances. It is evident, therefore, that The
rate of vibration and not the element
e1nployed-is the principal factor in pro-
ducing light.
Unfortunately all methods Of produc-
ing light by means of chemical combine
tons (such as the union Of the carbon Of
the candle with the oxygen Of tho air)
are accompanied by very large pro-
duction Of heat waves, which In thcma-
jority of cases are utterly useless, IL not
absolutely troublesome. The old sin1ile
of a musician desiring to produce cer-
tain high note being compelled TO press
down all the keys Of his instrument is
an apt one. The lower notes are not
merely useless, but they are positively
annoying,
Singulariy enough, the FIRST solution of
the problem that was attempted success
fully was by the aid Of heat A very
small amount of light waves are required
for recognition by the wonderfully de-
veloped special sense which man pos
sesses. lis intensity, not quantity, that
is wanted, to use technical term. Con-
sequentiy If very small particle is heat
ed to incandescence the light which it
throws out bears far greater ratio to
the amount Of heat required than 1t does
If a large mass is similarly heated.
This Is one Of the radical bases Of the
utility of the incandescent electric light.
An extremely smell f1ament is heated to
incandescence through the resistance
which 1t offers to the flow Of an electric
current. It generates heat, it is true,
but the amount of heat thus produced is
directly proportional to the mass of the
carbon, which is very small. The light
produced, however, is amply sufficient
for all ordinary purposes.
This solution, however, is highly un-
satisfactory to scientists, however useful
from heat altogether was wanted. The
firefly, the phosphorescent sea animal
cules and even the exhausted tubes Of
Geissler furnished the hops that there
was yet some method Of reaching tho
high note without pressing down the
whole keyboard.
Recently an extraordinary genius has
appeared in this country who seems
upon the verge Of discovering, If not to
have actually discovered, method by
which this might be done. Nikola Tesla,
man Of independent fortune and most
brilliant mind, who was for time con-
nected with Edison, has dared to expert
ment with rapidly alternating electric
currents. The result has surprised the
widest dreams of the theorizers. He
has succeeded in producing light of COM
paratively high intensity without the
production of heat and apparently di-
rectly by the use Of electricity. The
halls of the Royal society Of London and
of the Franklin institute of Philadelphia
have been illuminated by means Of the
Light radiated from bare copper wires in
the open air carrying these SO called
Tesla currents.
The wires were not hot, but they radi-
ated from their surface light and sent
from one to another bands and stream
ers Of the mysterious light which we see
in the aurora borealis. The effect must
be seen to be thoroughly appreciated,
but when it is stated that the expert
lnenter without difficulty succeeded in
radiating light not only from an ex-
hausted glass tube held in his hand, but
also from his thumb, his nose and other
features, the enthusiasm which swept
over his audiences in London and in
Philadelphia may be appreciated.
AS yet no useful application has been
found for these wonderful new develop
1nents in electrical science, but they
should be welcomed as harbinger Of
further progress. baltimore Sun.