The Portland daily press., 1891-09-22

Here A stands for the thick piece of glass.
and b is the film Of silver at the back. The
bit Of burning paper is at G, and the single
line 1, drawn sSd from shows the ray q light
Elected In the line marked L. The rest of the
light follows the dotted line through the
glass, and their turns over the next dotted
line. and coming out Of the glass follows the
line msrked 2. AT the same time, part of
this reflected light is reflected back again
from the inner side of the glass, and going
back 1t strikes the silver again, and is once
more reflected and follows line g.
To understand how the inside of piece OF
glass will reflect light you have only to fill a
clear glass goblet with water, and holding ii
over J our head look up at the under side of
the surface of the water. 1t seems to be a
sheet of melted silver so light is the refection.
Dip your finger in the water while thus
tually reflected on the under side of the
water. Stand in front of window on a
moonlight night when the moon is just ris-
ing and look at the dark window, and you
will see two moons reflected in the glass.
One of these is reflected from the outside of
the glass, the other is from the inside of the
glass at the back.
AS we look at the reflections of the burn
ing paper we see that they are not equally
bright. To understand this look at the
drawing again. The light from @ is first re-
flected from the outside. but as the glass is
poor reflector the greater part Of the light
slips through and is returned from the
silver. Then at the third reflection only a
very little is kept back, the greater part es-
capes again at line 2, SO that there Is really
only very little lett to make reflection
No. 3. This is not by any means all that we
might learn from looking-glass. You will
notice that the line In the drawing is bent as
il enters the glass, and that the first retiec-
tion is exactly right angle. These things
are quite as strange as the three reflections,
and perhaps, another time we will get up
some experiments to show what they mean.
The ForgetfuI Pupil.
LHaIper's Young People.l
There once lived a man who possessed
such lovely garden that it Yves his greatest
pleasure to watch its growth. as leaf and
flower and tree daily seemed to unfold to
brighter bloom. One morning, as he was
taking his usual stroll through the well-kept
paths, he was surprised to fipd that many of
the blossoms were picked to pieces. 1t was
not long before he traced the mischief to a
little bird. which he managed to capture and
was about to kill, when 1t exclaimed
"Please do not kill me. am only wee
tiny bird. My flesh is to little to satisfy
you. Set me free, and / shall teach you
something that will be of much use to you"
Woulu ike 10 put an emu 70 you, re-
piled the man, for you are spelling my gar
den; but as am always glad to learn some
thing useful, shall set you free" And he
opened his hand to give the bird more air.
Attention." cried the bird. "Here are
the notices which should guide you through
life: do not cry over split milk; do not de-
sire what Is unattainable; do not believe
what is impossible"
The man was satisfied with the advise and
let the bird escape, but 1t had scarcely re-
gained its liberty, when, from high tree op-
posite, 1t exclaimed
escape II you only knew what you have
What have lostP' the man asked, an
grily.
Why. i you had killed me. you would
have found inside Of me a huge pearl as
large as goose's egg, and you would have
been wealthy man forever"
"Dear little Bird" the man said, In his
kinGest tones, sweet little bird, will not
harm you. Come down to me, and 1 will
treat you as though you were my own child,
and give you fruit and flowers all day."
But the bird replied: "What a silly man.
to forget so soon the advice gave you!
told you not to cry over split milk, and here
you are worrying over what has happened.
urged you not to desire the unattainable, and
now you wish to capture me again. And
finally, babe you not to believe what Is i'm
possible, and here you are imagining that
have huge pearl inside of Inc, when a
goose's egg Is larger than my whole body.
You ought TO learn your lessons better in
the future" added the bird, as it flew far
away.
Scientific Fun.
A trick that is ingenious rather than scien-
tifc. and that combines something, too, of
optical Illusion, is easily tried, in this
way. Place an ordinary dinner plate edge.
wise upon your knees, against the edge Of a
table, the concave side toward you. Keep
the spectators on the opposite side of the
table Lay the blade of table-knife lightly
hatwise on the edge Of the plate, as II the
latter were knife-grinder's wheel and you
were going to sharpen the knife. A very
slight but rapid trotting movement of the
Knees, easily done by muscular contraction,
VIII make the plate raise and fall, though
but fraction of an inch. IL this is dex-
trously done. and the knife manipulated as
though 1t were getting a fine edge. il will
appear to the spectators that the niata 10
rapidly revolving like wheel, -