Изобретения и изобретатели. Учебно-справочное пособие для изучающих английский язык

It is a slender rod of a solid marking substance, such as graphite, enclosed in a cylinder of wood, metal, or plastic; used as an implement for writing, drawing, or marking.

Invention of the Pencil. In 1565 the German-Swiss naturalist Conrad Gesner first described a writing instrument in which graphite, then thought to be a type of lead, was inserted into a wooden holder. Gesner was the first to describe graphite as a separate mineral, and in 1779 the Swedish chemist Carl Wilhelm Scheele showed it to be a form of carbon. The name graphite is from the Greek graphein, “to write.” The modern lead pencil became possible when an unusually pure deposit of graphite was discovered in 1564 in Borrowdale, Cumberland, England. The pure graphite was sawn into sheets and then cut into square rods. The graphite rods were inserted into hand-carved wooden holders, forming pencils. They were called lead pencils by mistake – at the time, the newly-discovered graphite was called black lead – it looked and acted like lead, and it was not known at the time that graphite consisted of carbon and not lead. The English had a monopoly on the production of pencils since no other pure graphite mines were known and no one had yet found a way to make graphite sticks.

The Germans manufactured graphite sticks (made from powdered graphite), but they were impractical. The breakthrough in pencil technology came when French chemist Nicolas Conte developed and patented the process used to make pencils in 1795. He used a mixture of clay and graphite that was fired before it was put in a wooden case. The pencils he made were cylindrical with a slot. The square lead was glued into the slot and a thin strip of wood was used to fill the rest of the slot. Conte’s method of kiln firing powdered graphite and clay allowed pencils to be made to any hardness or softness by varying the ratio of graphite to clay.

The more graphite used, the “softer,” or darker, is the mark made. Some pencil manufacturers use the letter “H” to indicate a hard pencil. Likewise, a pencil maker might use the letter “B” to designate the blackness of the pencil’s mark. Pencil makers also use combinations of letters – a pencil marked “HB” is hard and black; a pencil marked “HH” is very hard, and a pencil marked “HHBBB” is very hard and really, really black! In 1812 the American William Monroe invented a process still used today by which the graphite-clay mixture could be encased between two pieces of cedar wood.

In 1861, Eberhard Faber built the first pencil factory in the United States in New York City.

The mechanical pencil, patented in 1877, consists of a cylindrical piece of pencil lead inserted into a metal or plastic barrel against a movable rod that can be adjusted by a screwing motion to expose part of the lead. The basic design of the mechanical pencil changed little until a modification of a mechanical drafting pencil was introduced in 1976. Originally marketed as a trade tool for engineers, drafters, and artists, the thin-lead mechanical pencil is now used by the general population.