Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1890-09-28
ABOUT THE MAGNET.
The Peculiar Form of Energy Stored
Up in it is Magnetism,
AND is KNOWN ONLY BY EFFECTS,
Lines of Force and How They Act In Rela-
tion to Each other.
THE PRINCIPLE OF TIE COMPASS
WRITTEN ron THE prsrArcH.1


are both natural and artificial. In the nat
ural state they are called load-stones. In
the artificial state they are called steel or
permanent magnets, and temporary or elec-
tro magnets. A permanent magnet is made
of steel, and when once magnetized il re-
tains its magnetism as its name implies. An
electro magnet is piece of soft iron forming
a core to an electric coil. It might well be
likened to spool of thread, when the spool
would represent the iron core or magnet
proper, and the thread the electric wire.
The iron core is magnetized, or made mag
netic, during such time only as there is an
electric current flowing through the wire
coil.
Let us first study the permanent or steel
magnet and its properties. We do not
know what magnetism is, except that it is a
form of energy, and therefore condition OF
things In fact, magnetism is simply q
name given to certain condition OF things
which we recognize by its properties. For
example, when we see piece of steel at
tract bits of iron, we call the steel magnet,
and in this way distinguish it from piece
of steel that will not attract bits of iron.
ONLY KNOW IT'S EFFECTS.
But as far as magnetism itself is con-
cerned, we do not know what it is any more
than we do what gravity or electricity are.
However, this fact does not hinder our
studying magnetic laws. We do not know
what gravity is, and yet we know all about
its laws, and, recognizing its effects, we say
"gravity did this or that" If we wished to
we might call gravity magnetism and mag
netism gravity, for all the difference it
would make. They both possess the profit
OF attraction. However, we wish to distin-
guish between the attraction OF the earth
for all things, and the attraction of magnet
lied steel for bits of iron, so we call one
kind of attraction gravity and the other
magnetism.
Now, as magnet possesses the power of
attracting to itself bitsot iron that are some
little distance away, we might easily i'm
agine that magnet must in some way
effect the space surrounding it. In fact this
is actually found to be the case and Is
shown in the following manner,
LINES OF FORCE.
Take good bar magnet "a bar magnet is
straight, but most steel magnets have the
shape of horseshoe), lay it on table, and
place over it fat piece of glass. If we then
sift fine iron filings over the surface of the
glass, the filings will arrange themselves in
curved lines reaching from pole to pole, and.
in fact, it is found that these lines rad1ate
out from each pole ON all sides, much like
the lines or grooves of muskmeIon, only
there are a great many more OF them. These
lines are called 'lines of torce," but what
they are we do not know. We only know of
their existence by experiment, and recog-
nize them by their effect.
of f,,
force have closed circuit; that is, they
start out from one pole into the span around
the magnet, and. curying toward the other
pole, they re-enter then and so return
through the magnet to the starting point.
1t must not be understood here that there is
anything like a motion or a current con-
nected with these closed Zines OF force"
They are simply thin; and now let us see |
what use we can make of them. /
LINES OF TWO MAGNETS.
Although these lines have no motion,
hey seem to have direction, for if we |
bring two magnets near to each other, so |
hat one magnet is free to move, that is, if |
We take two bar magnets and Law one on the |
able and suspend the other over it with a |
'tring, the hanging magnet will always set
tselt parallel to the other magnet in such a |
way that the north or positive pole of one
magnet will be over the south or negative
pole of the other. In other words, unlike
poles seem to attract each other.
But if we examine this little further we
ind that the lines of force of the two mag
lets are parallel to each other and in the
anne direction. That is if we imagine the
direction of the lines to be out of the north
,ole and into the south, the lines of the
wo magnets will then be parallel and in
he same direction, for the lines will pass
nut of the north pole of one magnet into
he south pole of the other, and out of the
lorth pole of this back into the south pole
f the first again. If we reverse the poles
# the two magnets, SO that the lines of
orce are opposed to each other. we will
STRAIN THE LINES
ut OF their natural position, Just like
rubber band or bending a
pring, and if we let 60 of the suspended
Magnet rubber band and spring, all will
eturn to their natural positions, and in
loing so, can be made to do an amount of
work exactly equal to the work or energy
in straining these things out Of
heir natural positions.
Suppose now that we have two magnets
md only know the poles of one of them; it
would be very small matter to find the
ther, and not only to find them, but at
nee tell which one was north and which |
outh. Suppose that the unknown magnet
we're round like ball, and it is Just as easy
o make a magnet this shape as any other.
We can now explore the space surrounding
he magnetic ball and find out all about it.
% do this all we need is a small steel
eedle, we'll magnetized and suspended
rom the middle by fine thread. Now,
emem bering this rule, that a magnet tree
D move will set itself parallel to the lines
f force of any other magnet near it and in
uch a way that the lines of force OF the two
,agnets will have the same direction, let
s suspend our little exploring magnet over
he magnetized ball.
MYSTERY OF THE DIP.
At first it will twist and vibrate back and
nth, but finally it will come to rest par
Ilel to the lines of force of the ball magnet
nd in such q way that the lines coming !
ut of the north pole of the ball will pass
ito the south pole Of the needle, and from I
,e north pole of the needle into the south ]
ole of the ball. IF the needle comes to rest
a position tangent to the ball it will be
lst half way between the two poles of the .
sll, If the needle dips little, it will be
carer one pole Of the ball than the other,
nd il the needle dips to such an extent &
lat it points to the center of the ball it is Q
rectly over one of the poles.
And in each case the north pole of the j
,edle will point toward the south pole of {
e ball, so that the lines of force may pass e
ON the north pole of one magnet to the .
nth pole of the other. Now, it is exactly =
this manner that we are enabled to find 4 s
lr way about on the surface of the earth, p
r although the earth is not a magnetized a
On ball, yet it has the properties Of mag =
It and will cause suspended magnetized