Bismarck daily tribune. [volume] (Bismarck, Dakota [N.D.]) 1881-1916, 1912-10-22
WAVES Of Llg !!
They Vary h Length and on That
Account Vary In Color.
OUR SUNLIGHT IS PURE WHITE

n" M
OUR SUNLIGHT IS PURE WHITE
The Arc Light 10 lts clessst Rival.
With Its 10000 Candle Power Per
lneh-Ths Way 4 Human 0slns With
X Ray cysa Mould % Handicapped.
Light travels at a speed Of $4,000
miles a second. The source Of all light,
except the light from Hrefles and their
kin. is 4 substance raised to a tempera-
turc sufficient to set up waves In tho
surrounding ether. Light waves vary
In length between 1-33iOO and l.8jON
OF an inch, the lrst being extreme red
and the second being extreme violet.
Rays OF white light have a length Of
l-450OO Of IN inch. The sun Is u great
mass Of white hot matter.
In IN arc lamp 1t Is the white bot
particles OF carbon floating between
the two electrodes which produce light.
In the incnndcscent lamp it Is the hair.
pin tilanent inside the glass globe
which, when heated by electricity,
gives off light waves In gas and oil
lamps light Is produced by the heated
particles Of carbon In the Dame above
the wick o mantle. The eye can
stand without firing a brllliancy OK
about Ave ~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 1lainent
incandescerfts give about 1000 candle.
power
The prism shows us that white light
Is composed Of a happy. blend Of al!
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 mantles give a greenish
light, open fame n 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 rcd gives of only waves
Of q length to produce that particular
color. A,body appears red because It's
surface absorbs all the other waves and
rejects the red waves back into the
eye. A thing looks black when 1t Is
capable Of absorbing all the colors ut
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-.
ihg 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 Mt best. AS VIC all know.
there are times when all appears black
to Us and yet animals a see. The
trouble is the faint light rays move
too slowly 10 be registered on the hu.
man retlna. The \ ray hns proved bc.
yond q doubt that there are light rays
which move too fast for human eyes
to register. This light p%enetrates books.
wood. paper and 81 human flesh.
With the X rays to assist our eyes
We can see the bones in our arm with.
out botherlng to remove our shirt. But
q man with x ray eyes would be sadly
handicapped in this world. for he could
see nothing but solids. such as earths
and metals. and would be unable TO
see q board fence at all. TO US all Is
darkness beyond what u eyes will
register.
Light rays themselves are Invisible.
When they move through the ether
alone our eyes cannot see them: con.
sequently all Is total darkness. But
when they meet with the resistance Of
our atmosphere. producing heat. they
register on the retina. and. behold.
We can see. As the atmosphere thins
rapidly rs we go upward. so. in pro.
portion. the air resistance diminlshes.
and consequently the heat Of the sun
seems to grow less. This explains why
the tops Ot very high mountains are al.
ways covered with snow.-New York
Press.
Simple Directions.
They were telling stories Of the late
Andrew Lang in M Of the clubs tile