Ask who invented the modern pencil and the answer depends on the source. One art reference says Nicolas-Jacques Conté set out to make graded pencils around 1790, when France was cut off from English graphite. A news account puts the French war minister's request to him in 1794, and several sources say he patented the process in 1795. Conté's method started with a mixture of water, clay and graphite; one history says he roasted it in a kiln at 1,900 degrees Fahrenheit and then set the resulting soft solid in a wooden case. His great advantage was control. By changing how much clay was in the mix, a maker could choose how hard or soft the pencil would be.
The letters printed on a pencil say how hard it is. H means hard and B means black. The most popular middle grade, HB, sits midway between them. The higher the B number, the more graphite is left on the paper. The letter F stands for fine point and is a hard pencil for writing rather than drawing. Behind every letter is the same trade: more clay gives a harder core and a lighter line, and less clay gives a softer core and a darker one; the Thoreau family pencil business in New England offered pencils from No. 1, the softest, to No. 4, the hardest, and that numbering survives today. Since the 1960s, American students have mostly used No. 2 pencils. A No. 1 pencil smudges easily, while a No. 3 is harder and breaks more easily.
Graphite's early story is tied to the Lake District of England. A local legend says a storm toppled a tree in the 1500s and its roots came up with a shiny black mineral. The story may not be true, but within a few decades the site had become the first commercial graphite mine. Local shepherds first used the graphite to mark their sheep, and because it looked like lead it was called plumbago or black lead. The purest lump graphite deposits were at Borrowdale, near Keswick, and they fed a smuggling trade there. A book by John Barrow dates the discovery of the purest lump deposits to 1564 and says the local black economy grew up around it. In the nineteenth century a pencil industry grew in Keswick to use the high quality graphite that the mines produced.
Cumberland pencils were of the highest quality, the book says, because Borrowdale graphite shed no dust and marked paper very well. The first pencil factory there opened in 1832. By the 2000s the local mines had long been closed, and the graphite used came from Sri Lanka and other faraway places. A product that began as a local mineral had become a global supply chain. Today there are two main ways to shape a core. In one, a graphite and wax mixture is forced through a mold into spaghetti-like strings, which are cut and dried in ovens. In the other, a graphite and clay mix is squashed in a billet press into a solid cylinder, then forced through a mold that slices off strips the size of a pencil core.
Incense-cedar began as a substitute for Eastern red cedar in pencils. Red cedar was the premier pencil wood from the mid-1800s into the early twentieth century. In 1910 the Hudson Lumber Company, owned by the Eagle Pencil Company, opened a slat mill in San Leandro, California, to use the cheaper supply of California incense-cedar. A cedar slat mill says the wood machines to a very smooth surface and sharpens well. The same mill says incense-cedar is stable, standing up to changes in heat and moisture without warping, checking or shrinking, and that with few resin canals or pitch pockets it takes paint and stain smoothly. The tree grows in the inland forests of central and northern California and southern Oregon; it makes up only about five percent of the trees in a typical stand, and it has never been grown in single-species plantations. The company that sells its slats says the tree regrows readily on open ground; that is the seller's claim.
Words to know
- graphite: soft carbon form
- plumbago: old name
- smuggling: secret trading
- stable: not changing
