Knoxville journal. [volume] (Knoxville, Iowa) 1874-1986, 1874-06-25
Youths Department.
A TALK ABOUT ELECTRICITY.

A TALK ABOUT ELECTRICITY.
"Do look here, Miss Horton! Isn't il
curiousi" And group, OF eager chill
dren gathered around the desk where their
laid down her book and said: "Well,
Eddy, what is it that is so curiousg"
"Why, l was rubbing this piece of glass
near some pieces of paper they came
right up to it, just as piece of iron does
to a magnet"
at must be a magnet" said Phoebe
thought, though, that they were al
WAYS of iron, and would attract nothing
else. Isn't it the strangest thing you ever
SAW"
"No," said the teacher, " it is not mag.
net, nor is it any stranger than that the
magnet should attract iron.'
"Then what makes it draw the paper to
it?"
There are many other things besides
magnetism which tend to draw bodies to
each other. In this case it is due to cleo
tricity."
"But all glass doesn't attract paper; MOI
will this, now" said Eddy, vainly attempt
ing to repeat the experiment.
"No, it is only when rubbed with
wooden, silk, or some such substance that
it will do so. Electricity is of two kinds,
called positive and negative, which exist
in all bodies, generally in neutral state
that is, as much of one kind as another
When piece of glass is rubbed with a
wooden cloth, the friction separates the
two electricities; the negative going to
the cloth while the positive remains in
the glass. Now, because all bodies have
altendency to become neutral, each kind
attracts the opposite and repels the same
kind; and it is the same with any body
which is charged with electricity. Such
bodies will also attract those which are
neutral"
"If," said Joseph, "all bodies con-
tain electricity, why do they not draw the
paper when rubbed? Iron or wood will
not"
because these bodies are conductors
that is, they will allow the electricity to
pass through them freely, and as fast as
the electricity is separated one kind flows
| off through the hand or whatever ii rests
on, while the other kind flows into it,
| keeping it neutral all the time. But glass
| is a non-c conductor and does not allow the
electricity to escape readily. 1t is par.
tial conductor, however, and if charged
will return slowly TO q neutral state
This was the case with the piece Eddy
has, when it would aot pick up the bits
OF paper"
but thought Electricity was fire."
said little Jennie. Father says light
ming Is Electricity; and it was lightning
that burnt Mr.. Mead's barn"
"When the tension of electricity is so
great as to cause 1t to pass through non
conducting substance it has the appear
ance of sparks; or if the tension is very
great, or the resistance small, IL passes
| like flame. When at rest, or passing
through conducting body, it is invisi-
| BILE. If we were to rub a piece of gutta.
| percha or sealing-wax il would become
charged with negative electricity. Then
if we should hold it near piece of glass,
positively charged, the tension would be
so great that the electricity would escape
| from one to the other through the air,
which Is a non-conductor in the form OF
sparks" ...
81 should think that you might light 0
fire in that way" said Eddy.
so they could" replied the teacher
"Sufficient heat may be produced by al
| electrical current not only to light fires
| but TO melt metal and even turn it into
vapor, so that IL will pass Off into the all
! like steam. The most brilliant artificial
| lights which can be produced are made
| in the same way. In the case Of Mr.
| Mead's barn, cloud charged, perhaps
with negative electricity passed over it.
This would draw the positive current to
| the surface Of the ground, and when the
| tension became great enough the cleo
| tricity would escape from the cloud with
a loud report, and striking the barn would
of course set ii on fire. Sometimes il
passes from the earth to the cloud"
but can spark be drawn from any
thing that is electrified ?" said Joseph.
Eyes; and from anything through
which an electric current can be passed.
Wouldn't you think 1t strange to see any
one touch off gun with piece of ice 7"
How funnyp exclaimed Eddy; while
Phoebe said: "Could one do that! l
should think ice would put out fire."
81 have seen it DONE" said Miss Hor-
ton. "The person who does it stands on
piece of glass and the gun is suspended
| by silk cords. These substances are non
conductors, and so do not allow the cleo
! tricity TO pass through them. Then the
cone of the gun is connected by wire to
the negative pole of galvanic battery,
an apparatus by which electricity is pro-
duced. The person who shoots the gun
takes hold with one hand Of wire at
tached to the positive pole, and with the
other hand brings piece Of ice near the
cone. A spark will then pass between
the ice and the cone which will ignite
the powder and shoot the gun. But as it
is time for school now we cannot talk
any longer this time."-Om Ftreside
Friend.