The times. [volume] (Richmond, Va.) 1890-1903, 1891-02-08
FOR THE YOUNG FOLKS.
rlcrs AND FASCIEs LIKELY TO
PLEASE THEM
The velocity Of Light-scme Pleasant Illus
trst,ons Of How 1t Traverses space-Tot and
the Turtle-A Motheriy Dog and Her Family
of Adopted Children.


II Won could take all the people in the world
and set them out in space mile apart, IKE
mile-posts along railroad. and then at the
farther end use all the dogs and cats 10 ex-
tend the line Of mile-posts, you would run far
short of material to mark the distance
ont 10 the earth's brother planet, Neptune
Again. if YOU could use all this material OF
men. women. children, dogs and cats, and
put them out so that they would be as FAR
from one another as Boston is from San fran-
c;sco. vour line wouldn't be half long enough
70 reach TO the nearest star. IN -
On a clear night the average eye Will read
ilv see stars as low as the sixth magnitude.
Such a shining beauty as SIRIUS winKs at you
10 archly that il seems almost imposslDle
that wears are consumed in the passage OF us
rays TO the earth. when we remember thaI
liebt travels more than one hundred an eighty
Thousand miles in a second. Yes, If the near
est of the beautiful twinklers should be blot
ted ont at this moment we should still see IT,,
without the slightest change IN appearance,
two or three years after Chicago cleans up the
debris of the Worlds Far.
Rut even "A star so far away as that seems
nearly within touching distance when we find
that other stars, visible with the telescope, are
no far away that, sOr all we know. they may
have been blOtted cut before Cam ana ADel
were born. That is to say. that If one OF those
far distant orbs had been utterly annihiiaieu,
as you would snuff out n candle, when Adam
and Eve were enjoying themselves III the
Garden of Eden, the rays then starting 70,
ward the earth, Notwithstanding the. awful
upeed of light, could not get here In time 10
meet the closing of the nineteenth century.
How do we know that light travels at such
wonderful speedY Up 10 about two hundred
and twenty-five years agolt was supposed ina,
rays of light from all the celestial 0rbs passed
instantly 10 the observers eye. The old as
tronomers, in fact never took thought Of the
matter at all. They simply saw the sun ana
the stars. but they never dreamed that the
rays from them had TO journey Millions bill
lions and trillions Of miles in getting 70 mum
dane eyes. IL was the great fortune OF
Danish astronomer TO make the discovery that
light. as well as sound or railway tram, re-
Quires given time 10 travel gwen distance
Roemer the famous Dane alluded TO, was
led 10 his discovery by observations of the
eclipses of Jupiter's moons. He found That
there was a difference of several minutes IN
these eclibses; that they occurred earlier
when the earth was on the side OF the sun
nearest 10 Jupiter and later when farthest
away. With this data as a starting point, he
soon found that the difference of apparent
time resulted from the time required for light
10 travel across the diameter of the earth,s
orbit, about one hundred and eighty-two mil
hon miles. This time proved to be about six
teen minutes. and as half that would be the
time from the earth to the sun, the mystery
was solved.
The accuracy of this calculation has since
been verified by other methods, and all au-
thorities now agree that the velocity of light
is not far from 10000 miles second Ii is
difficult for the mind to grasp and comprehend
such speed The swiftest animate thing is
undoubtedly the pigeon. which has been known
TO travel hundreds of miles at the rate Of fifty
miles an hour. little arithmetical exercise
will show that it would take pigeon more
than two hundred years TO cover the distance
TO the sun at fifty miles an hour without a
stop, and to 60 as far as Neptune 1t would take
the bird nearly a thousandyears.
When we want an illustration of speed we
often use the expression swift as a cannon
ball" But If you could fire q cannon ball to
the sun when you are u college freshman,
your hair would be sprinkled with gray when
the ball stopped, for you would be seventeen
years older than when You fired the shot.