Story of Graphite

GRAPHITE is an allotrope of carbon, chemically related to diamonds. Originally referred to as ‘black-lead’, it has been known severally as wad(d), kellow, black-calke/cowke, and plumbago; even today, it is not uncommon to refer to ‘lead’ pencils. Its existence as a mineral was established in 1779 by a Swedish chemist, Carl W. Scheele; a decade later it was given the name ‘graphite’ by the German chem- ist and mineralogist, Abraham Gottlob Werner, a term derived from the Greek word ‘graphein’, meaning to draw/write.

Historically, it has had a number of uses, notably as a lubricant, but has also been used in anything from lining the inside of casting moulds of cannon and musket balls, to the manufacture of baseball bats and golfballs, as well as in the nuclear and aerospace industries. Until well into the nineteenth century, it was also recommended for minor medical conditions, such as colic or dyspepsia, sometimes taken with nux vomica.

As a material for artists, it appears to have been in use by the mid-sixteenth century. Initially, it would have been applied it in its pure mineral state, either as a baton wrapped in sheepskin or string, or using a wooden or metal holder, known as a porte-crayon. Wood-cased pencils, in a primitive form of those we know today, seem to have been available from the end of the seventeenth century; soft woods such as deal, pine and, especially cedar were preferred for ease of cutting and sharpening.

Finest English graphite, from Borrowdale in Cumbria, soon became a highly prized commodity, encouraging pencil makers to experiment with ways of finding a cheaper alternative by using lower grade graphite, mixed with binders and other substances. In 1662 the Bleistiftmacher (lead pencil maker) Friedrich Staedler of Nuremberg, devised one of the most successful

of these early composite pencils by mixing ground graphite with sulphur and antimony, and inserting into wooden shafts; however, while they were an improvement on earlier admixtures, they were still liable to break more easily than pure graphite, and left a less clear
mark.

A truly viable substitute for pure graphite emerged only at the end of the eighteenth century, as an economic imperative brought on by wartime embargos. Dwindling supplies from mines in Cumberland, exacerbated by a trade blockade during the war between France and England from 1793, deprived Continental pencil manufacturers of imported Borrowdale graphite, and prompted

a national effort to invent an equally performing alternative. In 1794 the painter, chemist, physicist and engineer, Nicolas-Jacques Conté responded to the challenge set by the French Minister of War, Lazare Carnot, in just eight days. The following year, he was granted a patent for his new process, which involved mixing low-grade, finely-ground graphite powder, readily available in France, with clay and water, and placing the pastes into narrow moulds that were then fired at high temperatures, and then inserted into grooved wooden batons.

In 1798, three years after Conté’s invention, a counter-claim for the invention of this new form of ‘composite’ graphite pencil was made by the Austrian mechanic, Josef von Hardtmuth, who opened a pencil factory in Vienna in 1790. While precedence is impossible to establish, Hardtmuth’s discovery only serves to highlight the drive to invent a modified form of graphite pencil, stimulated by economic necessity.