Show BLACK LEAD PENCILS Some Unfamiliar Facts About a Very Familiar Object It is difficult to determine the exact period in which black lead was first utilized as an instrument for writing or drawing as it has been confused with other mineral bodies to which it bears b ars no relation says the Scientific Amer American AmerIcan American ican The ancients used lead but bilt the metal was formed Into fiat flat plates and the edges of these plates used to make the mark marl If an was desired the th transcriber drew parallel lines and traced their illuminated de tie designs designs signs usually with a hard point but also with soft foit lead That lead was known to the ancients is also proven proven by the tact that it is mentioned in the book of Job Tob During the year 1615 there was a de dH description d of ot the black lead pencil writ written written written ten by Conrad Gesner He H says that pieces of plumbago were fastened In a wooden handle and a mixture of fossil substances sometimes covered with wood was used for writing and draw drawing drawing ing lug About half a century later a very ery good account of this mineral was given and it was then used in Italy Ital for draw drawIng drawIng drawing Ing and mixed with clay for manufacturing manufacturIng manufacturing turing crucibles We Ve are informed In His History History tory tor of Inventions that the pencils first used In Italy for drawing were com corn composed composed posed of or a mixture of lead and tin nothing more than pewter This pencil was called caned a stile Michael Angelo men mentions mentIons mentions this stile sUle and in fact it seems that such euch pencils were long used In common over the whole continent of Europe At this period the name plum plumbago plumbago plumbago bago or graphite was not in use but instead the name or mol b dolds which Is now applied to an en entirely entirely entirely different mineral mIneraI Graphite or black lead is formed in inthe Inthe inthe the primary rocks In the United States it occurs in and amI quartz in Great Groat Britain in greenstone rock and gneiss and ad in Norway in quartz The mine at Borrowdale England has sup supplied supplied supplied plied some of the finest black lead in tn inthe Inthe the world but the varies aries v o ow owIng owing Ing to the tho th irregularity which the mineral occurs The Jews were for a while the only manufacturers of It require l great skill to perfect the manufacture according o 0 the degree de ee of hardness or softness required Of recent years the manufacture of pencils has hab ha increased to such an extent that the price of these thes articles has decreased proportionately Graphite and pure clay are combined and used In the manufacture of arti artificial artificial lead pencils and on the other hand the greatest perfection is attained In the making of the higher class pencil Graphite Is Is exposed to heat to acquire firmness and brilliancy of color Sul Sulphur Sulphur Sulphur is also used u d to secure a more per perfect perfect feet color |