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years ago； when Mr。 Parkes gave a description of it；
from which I may condense a few particulars。
The mine is in the midst of a mountain about two
thousand feet high； which rises at in angle of about
45 degrees； and； as that part of the mine which has been
worked during the last century is near the middle
of the mountain； the present entrance is about a
thousand feet from the summit。 The opening by
which the workmen enter descends by a flight of
steps； and in order to guard the treasure within； the
proprietors have erected a strong brick building of
four rooms； one of which is immediately over the
entrance into the mine。 This entrance is secured by a
trap…door； and the room connected with it serves as a
dressing…room for the men when they enter and leave
the mine。 The men work in gangs； which relieve
each other every six hours； and when the hour of
relief comes； a steward or foreman attends the dressing…
room to see the men change their dresses as they
come up one by one out of the mine。 The clothes
are examined by the steward to see that no black…lead
is concealed in them； and when the men have dressed
they leave the mine； making room for another gang；
who change their clothes； enter the mine； and are fastened
in for six hours。 In one of the four rooms of which
the house consists there is a table； at which men are
employed in sorting and dressing the mineral。 This is
necessary； because it is usually divided into two qualities；
the finest of which have generally pieces of iron…
ore or other impurity attached to them； which must
be dressed off。 These men； who are strictly watched
while at work； put the dressed black…lead into casks
holding about one hundred…weight each； in which state
it leaves the mine。 The casks are conveyed down
the side of the mountain in a curious manner。 Each
cask is fixed upon a light sledge with two wheels；
and a man； who is well used to the precipitous path；
walks down in front of the sledge； taking care that it
does not acquire momentum enough to overpower
him。 When the cask has been thus guided safely to
the bottom； the man carries the sledge up hill upon
his shoulders； and prepares for another descent。
Up to about the middle of the eighteenth century the
mine was opened only once in seven years； the quantity
taken out at each time of opening being such as was
deemed sufficient to serve the market for seven years；
but when； at a later period； it was found that the
demand was increasing and the supply decreasing； it
was deemed necessary to work the mine six or seven
weeks every year。 During the time of working； the
mine is guarded night and day； and when a quantity
sufficient for one year's consumption has been taken
out； the mine is secured until the following year。
Several hundred cartloads of rubbish are wheeled into
the mine； so as to block up the entrance completely；
and this rubbish acts as a dam to prevent the springs
and land waters from flowing out； so that the mine
gradually becomes flooded。
When the Year's mining is concluded； the barrels
of black…lead are brought to market； and the mode
of effecting the sales was described by Dr。 Faraday
some years ago to be as follows： A market is held on
the first Monday of every month at a house in London；
where the buyers； who are generally only seven
or eight in number； examine each piece with a sharp
instrument to ascertain its hardness； those which are
too soft being rejected。 The person who has the
first choice pays 45s。 per pound； the others 30s。
But； as there is no addition made to the first quantity
in the market； the residual portions are examined
over and over again until they are exhausted。 At
one time the annual sale was said to amount to the
value of L40；000 per annum； but it has been greatly
reduced since。
A mode of applying manufacturing processes to
the preparation of black…lead is described by Dr。
Ure as being adopted in Paris。 The mineral； being
reduced to a fine powder； is mixed with very pure
powdered clay； and the two are calcined in a crucible
at a white heat； the proportion of clay employed
is greater as the pencil is required to be harder；
the average being equal parts of both。 The
ingredients are ground with a muller on a porphyry slab and
then made into balls； which are preserved in a moist
atmosphere in the form of paste。 The paste is pressed
into grooves cut in a smooth board； and another board；
previously greased； is pressed down upon it。 When
the paste has had time to dry； the mould or grooved
board is put into a moderately heated oven； by which
the paste； now in the form of square pencils； shrinks
sufficiently to fall out of the grooves。 In order to
give solidity to the pencils they are set upright in a
crucible and surrounded with pounded charcoal； fine
sand； or sifted ashes； the crucible； being covered； is
exposed to a degree of heat proportionate to the
hardness required in the pencils； the harder pencils
requiring the higher degree of heat。 Some of the
pencils are shaped in a curious manner： models of the
pencils； made of iron； are stuck upright upon an iron
tray； having edges raised as high as the intended
length of the pencils； and a metallic alloy； made of
tin； lead； antimony and bismuth is poured into the
sheet…iron tray。 When the alloy has cooled； it is inverted
and shaken off from the model…rods； so as to
form a mass of metal perforated throughout with
tubular cavities corresponding in size with the intended
pencil pieces； the pencil paste is introduced
by pressure into these cavities； and when nearly dry
the pieces shrink sufficiently to be easily removed
from the cavities。
The pencils just described are alike throughout all
their thickness； but in the majority of English pencils
there is a wooden holder to contain a narrow
filament of black lead running down the middle。 So
long ago as the year 1618 this mode was adopted； for
Sir John Pettus； who was deputy governor of the
Borrowdale mine under Charles II； in his 〃Fleta
Minor；〃 while； speaking of black…lead says； that 〃Of
late it is curiously formed into cases of deal or cedar
and so sold as dry pencils； something more useful than
pen and ink。〃 In a general way modern black…lead
pencils； are made by sawing cedar first into long
planks； and then into smaller rods； grooves are cut
out by means of a cutting machine moved by a fly…
wheel to such a depth as will receive a small layer of
black…lead； the pieces of the mineral are cut into thin
slabs and then into rods the same size as the grooves；
into which they are inserted； the two halves of the
case are then glued together； and the whole is turned
into a cylindrical form by means of a guage。
The kind of pencil called 〃crayon〃 is a mixture
of some kind of earth with a coloring substance。
The earth employed is sometimes chalk； and at other
times pipe…clay； gypsum； starch…flour； or ochre。 The
coloring