Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1912-10-01
Waves OF LIGHT.
Trey Vary IN Length and on That
Account Vary In Colcr.

Light travels 1T speed Of 10000
miles second The source of all lighr.
except the light from hreties and their
kin. T. Substance raised TO tempera-
Ture sufficient To set up waves in the
surrounding ether Light waves vary
In ieI<,. between l-:EIin and l-Ci-iGO0
OF hs inch. tire frSt being extreme red
aod the second being extreme violet
Rays Of white light have length or
1-4JOOO of an iach The sun is a great
miss Of white hot matter.
In an arc lamp 1t is the white hot
particles Of curbOn floating between
the two electrodes which produce light
In the incuudeSCent lamp II is the hair
pin hlaunent inside the glass globe
which. when heated 10y electricity,
gives OF light waves In gas and oil
lamps iight is produced by the heated
PARTICLES of carbon in the flame above
the wick or mantle The eye can
stand without tiring a brilliancy of
about five candlepower per square
inch OF surfu- 2. The ordinary candle
flame gives from two 10 three candle
power per square inch. while the sun
nt zenith gives 100000 candlepower per
square inch The arc light ranks next
10 sunlight. with 10000 candlepower
per inch and the best tungsten filamen:
incIndescents give about 1000 candle
power
The prism shows us that white light
Is composed OF happy blend of all
the cOlors of the spectrum. The sun
gives the only pure white light. with
tie arc lamp n close second. and the
metal filameut incandeScents taking
third place Sky light. such as comes
from the north on clear day. is blush
white Gas nantes give a Sreenish
light. open flame n yellow lie ut and
Kerosene IN orange light
In the dark no color exists. The
color Of light depends upon the length
81 the waves. The light source which
we know as red gives of only waves
OF length 10 produce that particular
color. A body app mrs red because It's
surface absorbs all tie other waves and
rejects the red waves back into the
eye. A thing looks black when 1t is
once
Light rays. being I'm active motion.
produce heat when they meet with re-
sistnnce in their path This Is why
black clothing Is warmer in summer
than white clothing. the resistance be.
inGlon the surface OF the white cloth
ing and nearer the skin when we wear
black
The eyes have only certain range
weak enough at best As we all know
there are times when all appears black
10 us and yet animals can see. The
trouble IL the faint light rays move
TOO slowly 10 be registered on the hu-
man retina The y ray has proved be-
yond II 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 Y rays to asSist Off eyes
we can see the bones in our arm with
out hOthering TO remove our shirt Rut
man with y ray eyes would he sadly
handicapped In this world. for he could
see nothing hut solids. such as enrths
and metals and would he unable TO
see board fence nj all To us all Is
darkness beyond what our 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 retlna. ind. behold.
we can see As the atmosphere thins
rapidly rs we go upward. so. In pro
portion the air resistance diminIshes.
and consequently the heat OF the sun
seems to grow less This explains why
the tops of very high mountains are al.