Brownsville herald. [volume] (Brownsville, Tex.) 1910-current, 1912-09-25
AWORLDM MYSTERY WAVES OF LIGHT. {
They Vary In Length and on That
Account Vary In Color.
OUR SUNLIGHT Is PURE WHITE
The Arc Light Is Its Closest Rival,
With Its 10000 Candle Power Per
lneh-The Way a Human Being With
X Ray Eyes Would Be Handicapped.

With Its 10000 Candle Power Per
Inch-The Way a Human Being With
X Ray Eyes Would Be Handicapped.
Light travels at a speed Of $4,000
miles a second. The source Of all light,
except the light from f~irefies and their
kin, is a substance raised to a tempera-
ture sufficient to set up waves in the
surrounding ether. Light waves vary
N length between 1-334O0 and 10000
Of an inch, the first being extreme red
and the second being extreme violet
Rays of white light have a length Of
$4,000 of an inch. The sun Is a great
mass of white hot matter.
In an arc lamp it is the white hot
particles Of carbon floating between
the two electrodes which produce light.
In the incandescent lamp it is the hair
pin filament inside the glass globe
which, when heated by electricity,
gives OFF light raves In gas and oil
lamps light is produced by the heated
particles of carbon in the flame above
the wick or mantle. The eye can
stand without firing a ~brilliancy of
about five candlepower per square
inch of surface. The ordinary candle
fame gives from two to three candle
power per square inch, while the sun
at zenith gives 100000 candlepower per
square inch. The arc light ranks next
to sunlight, with 10000 candlepower
per inch and the best tungsten flament
i~ncandescents give about 1000 candle
power.
The prism shows us that white light
is composed of a happy blend of all
the colors Of the spectrum The sun
gives the only pure white light, with
the arc lamp a close second. and the
metal filament incandescents taking
third place. Sky light, such as comes
from the north on a clear day. is blush
white. Gas nantes give a greenish
light, open flame a yellow light and
kerosene an orange light.
In the dark no color exists. The
color Of light depends upon the length
of the waves. The light source which
we know as red gives off only waves
Of a length to produce that particular
color. A body appears red because its
surface absorbs all the other waves and
reflects the red waves back into the
eye. A thing looks black when 1t IS
capable Of absorbing all the colors al
once.
Light rays, being in active motion,
produce heat when they meet with re-
sistance in their path. This is why
black clothing Is warmer In summer
than white clothing, the resistance be
ing on the surface of the white cloth.
ing and nearer the skin when we wear
black.
The eyes have only a certain range
weak enough at best. AS we ell know,
there are times when all appears black
to us and yet animals can see. The
trouble Is the faint light rays move
too slowly to be registered on the hu.
man retina. The Y ray has proved be
yond a doubt that there are light rays
which move too fast for human eyes
to register. This light penetrates books
wood. paper and even human flesh.
With the X rays to assist our eye:
we can see the bones In u arm with
out bothering TO emove our shirt. But
a man with X ray eyes would be sadly
handicapped In this world, for he could
see nothing but solids, such as earthf
and metals. and would be unable tc
see a board fence at all. To us all i:
darkness beyond what u eyes viii
register.
Light rays themselves are invisible
When they mov through the ethel
alone u eyes cannot see them; con
sequently all Is total darkness. Blu
when they meet with the resistance o.
our atmosphere. producing heat. they
register on the retina, and. behold
we can see AS the atmosphere thin'
rapidly as we 60 upward. so, in pro
portion, the air resistance diminishes
and consequently the heat Of the SUI
seems to grow less. This explains WIZ
the tops of very high mountains are al
ways covered with snow.-New Yorl
Press.