forty centuries of ink- 第47部分

IN　GERMANY；　1450THEIR　USE　IN　MEXICO　IN　EARLY

TIMESWHO　MANUFACTURES　LEAD　PENCILSEMPLOYMENT

OF　THE　COMPOSITION　OF　LEAD　AND　TIN

IN　MEDIAEVAL　TIMESBAVARIAN　GOVERNMENT　IN

1816　A　MANUFACTURER　OF　LEAD　PENCILS。



THE　black…lead　pencil；　under　many　circumstances；

is　a　very　useful　substitute　for　the　pen；　in　that　it

requires　no　liquid　ink　for　marking　the　characters　on

paper　or　other　materials。　The　peculiar　substance

which　fills　the　central　channel　of　the　stick　of　cedar

has　the　property　of　marking　when　it　touches　paper；

and；　as　the　marks　thus　made　are　susceptible　to　easy

removal；　a　pencil　of　this　kind　is　available　for　purposes

which　would　not　be　answered　by　the　use　of　pen　and　ink。



The　substance　misnamed　〃black…lead〃　contains　NO

LEAD　and　is　a　carburet　of　iron；　being　composed　of

carbon　and　iron。　It　generally　occurs　in　Mountain　districts；

in　small　kidney…shaped　pieces；　varying　in　size

from　that　of　a　pea　upwards；　which　are　interspersed

among　various　strata；　and　is　met　with　in　different

parts　of　the　world。



Its　principal　source　of　supply　until　about　1845；

when　it　became　exhausted；　was　the　Borrowdale　mine

in　Cumberland；　England；　which　was　discovered　in

1564。　About　1852　a　number　of　mines　were　opened

containing　this　substance　in　Siberia　and　from　which

place　the　best　products　are　now　obtained。



The　accidental　discovery　of　this　mineral　at　Borrowdale

was　during　the　reign　of　Queen　Elizabeth　who

made　many　inquiries　about　it。　The　name　of　this

mineral　was　locally　known　as　wad　（graphite）。　So

valuable　was　it　regarded　that　it　commanded　a　very

high　price；　and　this　price　acted　as　in　inducement　to

the　workmen　and　others　to　pilfer　pieces　from　the

mine。　For　a　number　of　years　scenes　of　great　commotion

took　place；　arising　out　of　these　depredations；　and

the　result　was　that　the　proprietors　adopted　such

stringent　rules　that　hardly　anything　was　known　of

the　internal　economy　of　the　mine　till　about　sixty

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　substance　is　yellow　ochre；　mineral　yellow；

chrome；　red　chalk；　vermilion；　indigoindeed；　any　of

the　usual　dry　colors；　according　to　the　tint　required。

Besides　the　earth　and　the　color；　there　is　a　gummy　liquid

required　to　combine　them　together；　gum　arabic；　gum

tragacanth；　and　in　some　cases　oil；　wax；　or　suet；　are

used　as　the　third　ingredient。　The　crayons　here　alluded

to　are　employed　rather　for　drawing　than　for　writing；

but　they　obviously　belong　to　the　class　of　pencils　in

their　mode　of　action。



The　ancients　drew　lines　and　letters　with　wooden

styles；　and　afterward　an　alloy　of　lead　and　tin　was

used。　Pliny　refers　to　the　use　of　lead　for　ruling　lines

on　papyrus。　La　Moine　cites　a　document　of　1387

ruled　with　graphite。　Slips　of　graphite　in　wooden

sticks　（pencils）　are　mentioned　by　Gesner；　of　Zurich；　in

1565；　he　credits　England　with　the　production。　They

are　doubtless　the　product　of　the　Borrowdale　mine；

then　lately　discovered。　In　the　early　part　of　the　seventeenth

century　black…lead　pencils　ar