The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1880-07-16
LEAD-PENCILS.
:" Black Lead" Not Lead at AIl-IIOw Pen.
ellis Are Made.


Probably there is nothing SO univer-
sally familiar in use, and also SO utterly
unknown TO the users in its nature and
origin as the common lead-pencii, the
consumption of it in this country alone
being estimated by the most competent
authority at seventy-eight millions per
year. Its very name, perpetuating the
old leaden plummet familiar among the
treasures of the boys first pocket, is a
missioner and mistake, "black lead "
having no more resemblance to lead
than chalk has to cheese. Most people
suppose the lead is melted and poured
into the hole i'll the pencil wood, but 1T
Is ground to an almost impalpable
powder, mixed to n paste with water,
made into long coil like wire by being
forced through a small hole Gust as
water issues from syringe), Strengthened,
and cut i'll lengths and baked like pot
terry. The "hardness is due TO an
admixture of clay. The pencil is made
i'll two halves 10y machinery mt a cheap
and rapid rate, and the processes, which
cannot be related here at length, are
among the most interesting i'll American
features. The material called "black
lead is as marvellous as India rubber,
although less protean. 1t Is simply
carbon, and is an enigma and bundle
of Inconsistencies. Its unlikeness to
lead is suggested by saying that its
weight is less than one-fourth that of
lead, and that while lead fuses at low
temperature, graphite is not friable at
any temperature known; on the contrary
no substance known surpasses it i'll re-
sisting heat. Carbon in ordinary anthra-
cite burns; carbon in graphite, refuses to
burn. A crucible of graphite, buried to
the top in mass of burning anthracite
carbon in carbon-not only refuses to
burn. but melts its metallic contents.
The diamond, as is commonly known, is
nearly pure carbon; but so is graphite.
The latter is the softest substance dug
from the earth: the diamond is the hard
est substance known. Subject the dia-
mond to sufficient heat, and it parts with
a mysterious something, leaving bit OF
soft and dissimilar carbon; but 1t has not
yet-unless we accept recent stories
been found possible to reverse the pro-
cess and add to the carbon that myster-
ious something. The purity of graphite
is extraordinary. 1t IS sometimes refined
until less than one-twentieth of one per
cent. of other matter than carbon is left
merely trace. The finest specimen
of gold ever found, probably, was one
from the Ural Mountains, which was
1896 per cent. fine, thus having 1.04
per cent of foreign substance, against
90 per cent in the finest graphite; or,
stating it in another way, the finest gold
had more than five times, and the aver
age gold produced has twenty to fifty
times as much impurity as the finest
Ticonderoga graphite. Assuming that
the diamond is perfectly pure carbon,
this mere trace of impurity is all that
separates the rare, hard, translucent,
costly diamond from the common, excess
sively soft, dull, comparatively valueless
graphite, scarcely one-half as heavy as
the gem; and yet the two are closely
alike and almost equal in their resistance
to fire. How these things are so is yet
among the secrets of natures laboratory.