The herald., 1897-08-29
ELECTRO-MACNET
JUST FOR FUN,
Plain Directions by an Ex-
pert Showing Boys How
to Make It.
REMARKABLE LIFTING POWER.
Good Sport, and You Learn a Lot
About Electricity Worth
Knowing.

Almost every boy has a horse shoe
magnet among his collection of odds
and ends, and even this may be made
source of much amusement but an
electromagnetic is far more interesting,
and may easily be constructed if one
knows how to set about it. Incidental
~, too, the young artisan will learn
much that is well worth knowing.
Electric magnets differ from steel
magnets in that they are made of soft
iron. and are rendered magnetic by the
electric current passed around them.
Such a magnet can be made of any
scrap of soft iron, from the size of d
piece of telegraph wire to that of a gil
gantic mass of metal weighing tons;
but for boys use a magnet of moder-
ate dimensions will answer every pur-
pose.
A double electric magnet Is shown in
the figures and Q; and as it is an mex
pensive piece of apparatus to manufac-
ture, any boy can make several of them
at the same time.
To begin with, obtain a piece OF soft
iron rod three eighths of an inch in di-
ameter and eight inches long. This is
to be bent in the form of U If it is
blacksmith from whom the iron is pur-
chased will quickly shape it for you on
his anvil. From an electrician, or a
store where electrical supplies are sold,
purchase a pound of No. Is insulated
or annunciator wire, such as is COM
monty employed for connecting electric
bells. burglar alarms, etc. Several coils
or wrappings of this around the soft
iron core will form what is known as
an induction coil.
Next get two large spools and saw
the ends off. making them little more
than one-eighth of an inch in thick
ness. and enlarge the holes in the CEN
tres of them so that they will fit over
the iron, in the manner seen in fig. 1.
Wrap a piece of MANILA paper about the
iron between the flanges, and stick it
be sufficient to nsulate the iron, and
it would be well to fasten the paper in
its wrappings with the shellac. The
wood f1anges should fit the iron very
snugly, and to insure them from slip
ping it would be good plan to attach
them to the iron also with shellac.
Through the back flanges bore small
holes close to the iron, as shown in
fig. 1, and from the inside pass an end
of the wire, leaving six or eight inches
around the top rod, wrapping it tightly
and evenly, just as thread is wound
on a spool; when the front end or flange
is reached, continue the wire up and
over the already wound part, and wind
the wire back again to the other f1ange.
In this manner the winding should be
carried on until the space between
f1anges is completely filled up. Wind
the lower spool in a similar manner, and
then connect one wire from one spool
with one from the other, leaving two
unattached wires as shown in fig. g.
After the wire has thus been wound in
a neat and compact manner, the out
side of each spool can be covered with a
piece of soft leather, kid, or enamel
cloth, to protect the wires from becom-
ing chafed and prevent short crcuiting.
The meaning of the term short cir
cuit' is this,-that the electricity is all
lowed to travel from wire to wire to
reach its destination by exposed parts
, of wires being brought into contact. in
stead of being made to pass around
the coil through the entire length of
the wire, as it should.
A single magnet can be constructed
in the same manner, by employing a
rod of the three-eighths inch iron six
fianges as shown in fig. /. 1t will have
less than half the power of the double
one, but for some uses is quite as good.
These magnets will of course be dead
and useless without an electric current;
TO produce the electricity necessary,
very good and cheap batteries can be
made in the following manner:
Obtain some glass jars four or five
inches in diameter and eight inches
high, and across the top Of each place
two sticks of wood so that a fiat piece
of carbon may be attached to one, and
a thick piece of sheet zinc made fast to
the other. The jars, zinc, and carbon
may be purchased at an electrical sup
ply store for a few cents each; but ii
is possible for a boy of an economical
turn of mind to employ the pieces of
carbon thrown away from the electric
arc street lamps. which may be picked
up on the ground near the lamps Sew
eral of these pieces may be bound to-
gether with wire and suspended in the
jar; and for the zinc, few scraps from
a tin shop may be rolled together and
fiattened with a hammer, and suspend
ed in the jar by bit of copper wire
soldered to them. The carbon and zinc
should be suspended in the jars far
cIOuSH dpdl " piENcil tiltiI tOutblIiS
each other. A purchased battery, with
carbon, zinc, and jar, should appear as
shown in fig. 3.
To charge the jars, obtain two or
three pounds of sal ammoniac and dis
solve it, using half a pound to the pint
of water; mix this in a separate jar,
and then pour the fluid into the battery
jars. filling them up to the dotted line.
To the zines and carbons, wires should
be attached. and to connect the batter
les in series the wire from one carbon
should be attached to the zinc of the
next battery until all the batteries have
been connected,-leaving unattached