Evening star., 1899-04-08
ARE MADE OF GRAPHITE
Lead Does Not Enter Into the Composition
of Pencils
Description of the Way in Which
They Are Turned Out by
the Million.
From School and Home.

From School and Home.
The first thing to be said about lead pen
ellis is that they are not lead pencils at all.
Once upon a time sticks of lead were used
for making marks paper and wood, and
the name has survived though nowadays
all the pencils filled with graphite, or
plumbago. This mineral is found in only
few places in the world-in Cumberland,
England, along the Laurentian ranges in
the province of Quebec, and at Ticonderoga,
Vt. The largest mines on this continent
are at the latter place.
The graphite is taken in the lump from
the mines and carried to the reducing mill,
where 1t is ground or pulverized in stamp
mills under water. The fine particles of
graphite float away with the water through
a number of tanks, collecting at the bottom
OF these reservoirs. 1t is packed in barrels
IN the form of dust and sent to the factory
Whefe tens OF thousands of lead pencils are
turned out every day. The pulverized
graphite is so fine that it really is a dust,
dinSy In color and smooth ana oily to the
touch. 1t is divided into various grades of
hneness by floating it on water from one
tank TO another. The coarse dust sinks to
the bottom of the first tank, the next inner
to the bottom of the second tank and SO on
down the line, the finest powder for the fin
est pencils settling in the last tank
IN another series of tanks the German
pipe clay, which is mixed with graphite to
secure the different grades of pencils from
very soit TO extra hard. is graded in the
same way by floating. The finest CLAW is
mixed with the finest graphite. being ground
tosether between stones, and the hardness
" tue pehcll IS secured by increasing the
proportion of clay in the mixture.
FOR the medium grades seven parts by
weight of clay are mixed with ten parts of
graphlte. After the graphite and ciay are
ground together the mixture is put in can
vas bags and the water is squeezed out I'M
der an hydraulic press, leaving a mass the
consistency of putty. The plaster is placed
in forming press, which is a small iron
cylinder in which solid plunger or piston
works up and down. A steel plate having a
hole the size and shape of the lead is
put under the open end of the cylinder and
the plunger pressing down forces the graph
ite through the hole, making a continuous
thread or wire of graphite. AS long as
this thread is moist it is pliable, but it be-
comes brittle when dry, so it is handled
rapidly. 1t is cut into three lead lengths,
Strengthened out, and then hardened in a
cruclble over coal fire. The leads when
taken from the crucibleS are ready for the
wood, which is pine for cheap pencils and
cedar for more expensive ones. When the
STRIPS OF wood are received at the. factory
they are run through machine which cuts
IN each one six grooves, round or square,
and at the same time smooths the face of
the wood
The filling of the strips is done by girls.
The first one takes a grooved strip of wood
IN her left hand and a bunch of leads in
the right. She spreads the leads out fan
shape, and with one motion she fills the six
grooves with leads. Next to her sits an
other girl. who takes the filled strips and
quickly and neatly lays on another grooved
strlp which has just been coated with hot
glue by third girl. The filled and glued
STRIPS are piled upon each other and put
IN IN press, where they are left to dry
The ends of the strip are evene . a under
Sandpaper wheel, and then the strips are
Ied INTO machine which cuts out the indi-
Nidual pencils, shapes them and delivers
them smooth and ready for the color and
polsh IN six streams. The colorng is done
VIII Win nquld dyes, after which the pencils