The Fairmont West Virginian. (Fairmont, W. Va.) 1904-1914, 1905-10-17
BLACK LEAD Z
THEIR MANUFACTURE ANr The ,aa-
TER;ALa THEY CONTAIN.

+l t5-, -------- -
THEIR MANUFACTURE AND THE ,aa-
TsR;ALa THEY CONTAIN.
The Piumbaiso Comes mainly Frara
bavaria nnd the Red Cedar Wood
From Elorida-How th. Graphite rs
Manipulated to Form the Leads.
The FIRST pencils in the modern sens.
were simply pieces of pure rln;abasu.
the more common name OF which ~
black lead or graphite. THIS rineri,
has always been rare. and as the very
qualities OF softness and b!acincss
which made II good to mark with maze
It also disagreeable to handle II was
not long before Il covering OF wood WIS
provided, partly to protect the hand
and partly to cconomlze the piumbago.
The best graphite in the world h,s
been taken from mines In Borrcwdale.
England. and In eastern Siberia. The
quality in both places was such thar
solid slabs OF II could be sawed out
and these in turn cut into the slender
strips which form the leads of mol.
crn pencils. The quality, however.
was not sufficient to permit this meth.
cd to bs adopted exclusively. The
Bo:rowdale mines indeed have long
since been exhausted. Most OF tho
graphite now comes from Bavaria
Plumbago for the best pencils now
undergoes number OF processes. 1t is
mined in irregular Jumps or In any
form in which 1t may be got ont most
cheaply. Shipped to the pencil fac.
tory. 1t is there ground aEd mixed with
finely pulverized clny in quantities
which depend upon the hardness or
softness which the pencils are to pos.
sess. For hard pencils, such as are
used by mechanical and architectural
craftsmen. the mixture is one part Of
plumbago to two parts Of clay. Tie
softer the pencil the greater the pro.
portion of plumbago.
The mixture is '.thinned' with wa
ter and repeatedly ground upt.l It is
perfectly smooth and free froal grit,
1t is then placed in canvas bag and
squeezed by machinery until eaaugh
water has been removed to leave u
tenacious. doughllke mass, from which
the leads IRE to be formed.
The dough" us 1t is called, Is
placed In strong steel cyliaLca, enc
end Of which Is perforated Wiz holes
of the same size us the leads watch 1t
!s desired to make. The pressure or u
slowly descending piston forces the
dough out through the holes In lon.
strings, which are quickly removed
and laid in croovet o. ~ c,catci
boards to straighten and dry.
The next step is the tcmpcrlag OF the
leads Ivy heating to red heat In cru.
clblcs. BY this process the hardness
or softness of the pencils IL still fur
thor 2odiled, Impurities are burned
out and the little strips of plumbagp
are considerably Strengthened. They
are now ready FOR TIER T.-osdln c.sas.
These in ail the better grades of pen.
ellis are made of red cellar, most Of
which comes from Florida. This wood,
better than anything else. answers tho
requirements Of softncss Gal straight
ncS1 OF grain and per,.::aency. ....
Tie, wood is sawed by machinery
into strips, two Of which when placed
| together are equal to the diameter of
the pencil. But IL the Iced IL to be
square the two strips are not of equal
thickness. That which co:.tans the
groove for the lead is the t.!.c::rr. Most
pencils. however, hare rou:..l leads,
and In this case tho two strips are of
equal thickness. and each contains n
scmicircular groove.
The lead is now Inherited In tho
groove and the two strips arc glued
together. When dry. they IRE passed
through circular cutter similar to the
SO called hollow bits by which the ends
Of ladder rungs are rounded ana dow
els are made. They emerge at the
other end perfectly rounded. Nothing
remains but cutting the sticks Into
suitable lengths, painting or polishing
and stamping with the makers name
and the degree of hardness.
Pencils made Of the pure graphite
would not DO superior to those In which
the graphite is mixed with clay. The
modern pencils possess not only great
er strength, but there ere fewer gritty
spots. and they correspond more regu.
larly to the marks which are stamped
upon them.-Edward wllliston Frentz
In Youths Companion.