The record-union., 1894-07-05

stick OF graphite and you have that which
is found in the hands of everyone from
the bootblack who keeps tally on his
Shines to the man who has no more
fatiguing labor to perform than clipping
coupons off Government bonds. 1t may
be because of this universal use or be-
cause it is such simple, innocent-look-
ing article as TO fail to excite investiga-
ton, but it is, nevertheless, a fact that
not one in hundred of those who find a
constant use for it knows how lead PEN
ell is made.
There is popular impression that lead
is one of the component parts, but this
lead proves TO be graphite, dug from the
earth, separated from impurities and
graded and mixed according TO the de-
grees Of perfection desi red and the uses
to which it is to be put. But small per
cent. of that mined sscan be used for pen
ellis; the rest is converted into crucibles,
paint, lubricants and the bane OF the
housemaid's existence. stove polish.
The first graphite mine worked to any
extent was the one discovered at Borrow
dale, Cumberland, England. in 1854. 1t
was not what wonld be considered a rich
lind i'll this day, but as the opening of a
new industry it was SO highly priced and
was so closely maintained as monopoly
that IN pursuance 10 All Act OF Parliament
the mouth of the mine was constantly
guarded by an armed force. Later this
preeaution was supplemented by limiting
the period of work To six weeks per year,
and flooding the entrance with wafer to
prevent invasion while standing idle.
PREPARING GRAPHITE.
The process of preparing graphite for
pencils at this time was the simple one
OF saving il into strips and placing
it in the wood. No previous mixing
or grading was done. The impurities
ii contained took the place of the clay
with which it is now mixed, and there
was no doubt enough gritty substance in
it to make 1t hard without baking. 1t was
not until other mines We're discovered,
thus furnishing competition, that any
Improvement was made in this method.
Then repeated experiments gradually led
to the manufacture of pencils of uniform
hardness and tolerable reliabIlity.
The only graphite mine OF any conse-
quence in America is located at Ticon-
deroga, n. Y, and owned by the Dixon
Cruclble Company. 1t resembles in Il
great many particulars an anthracite coal
mine, though the workings are much
deeper, some of them being $50 feet below
the surface. The graphite runs in nearly
vertical veins, inclosed in rock, and
when raised TO the surface it contains 80
to so per cent. of silica, sulphur, and
other impurities. The first process
through which it is put is to free it from
this foreign matter. This is done by
pulveriZing it under water, the particles
being carried by the current through
series of tanks. That intended for pen
ellis has by this process been reduced to
impalpable, luSterless powder, finer that
flour, which can be taken in the hand
much the same as water and retained
about as easily.
PENCIL-MAKING BEGINS.
After the graphite reaches this stage the
real pencll-making begins, and this same
powder, which is so fine that pinch OF it
can not be held between the finger and
thumb, is treated to second process,
which further reduces it. Sufficient
water is added to cause it to run very
freely and then it is turned into hopper,
from which it flows through series of
four tubs. The coarsest and heaviest
particles settle at the bottom of the first
tub, the next coarSeSt in the second, and
so on to the last. by which time the pow
der has all settled and the liquid runs off
clear. This process OF floating" has
separated and graded the particles much
more perfectly than could possibly be
performed by any direct handling while
in the dry state, and it is now only neces-
sary TO drain the tanks and remove the
deposit through the gates at the bottom.
For the finest pencils. that taken from
the last tub is used, and for the ordinary
and cheap grades that from the two pre-
ceding tubs will answer.
A peculiar kind of clay, which is only
obtained in Germany, and which has also
been treated in the floating process, is
now combined with the graphite in pro-
portions varying according to the degrees
of hardness deSired-for the medium
grades about seven parts of clay to ten of
graphite. Water is added until the COM
bination is about the consistency of
cream, and the mixture put through the
grinding mill in much the same manner
as paint, for the finest pencils as many as
twenty times, thus insuring the most per-
feet strength, uniformity and freeness
from grit in the leads. From the grind
ing mills 1t is put in stout canvas bags
and the water forced out by hydraulic
pressure, until the mass becomes as thick
as dough, and in this condition it goes to
the forming press. This machine is sim
ply small vertical iron cylinder having
piston driven by screw. a plate is
inserted in the bottom having an opening
the size and shape of the lead desired.
through which the dough-like combina-
tion is forced, curling round and round
d
wooden tray. At intervals this tray is
removed and the lead Strengthened out
and cut up into lengths sufficient
for three pencils. This handling must
be done peditiously. as The lead dries
quickly, and where it could formerly be
tied into loose knots if taken fresh, when
exposed 10 the air for little time it
cruin Dles almost with touch. After the
leads are cut into lengths they are put
into crucbIes and baked in kiln, from
which they emerge ready for the wooden
case.
For the cheapest pencils pine is used,
for the common grades an ordinary quail
ity of red cedar, and Tor all standard
grades the Florida Keys cedar. This lat
ter wood is both soft and close-grained,
and is considered so superior for the pur-
pose that the European manufacturers
are obliged to ship it from Florida. In
the mills at Tampa the wood is shaped
iuto pieces inches long, 81 inches wide
and 2-l6 OF an inch thick. Each strip is
wide enough TO make the halves of six
pencils and in this shape, trimmed Of
all supertuous wood to avoid all freight
charges, they are sent to the main factory,
where they are fed into machine which
cut six grooves for the leads and at the
same time smooths the face of the wood.
Filling the leads, as it is called, is done
by girls sitting at brass-covered ta-
bleS. The first takes grOoyed slip with
the left hand and bunch of leads with
the right, and spreading them out in
her fingers like the sticks of fan,
lays them in the grooves and passes
the filled slips TO the girl at the left,
who puts over it another slip, which
has just received coat of glue from
brush welded by a third. In an incred-
IDLY short time a stock of filed slips have
been glued together and are ready for the
I. a.
oughly dry. On removing them from
the press the rough ends and projecting