In 1795, a man named Comte invented a pencil made of
a mixture of graphite and some sorts of clays which were burnt in the furnace. "Simple" pencils
are made of graphite, which leaves a dark trail on paper. In the process of pencil manufacturing, dry graphite powder is mixed with clay and water. The more clay there is, the harder the pencil and the more graphite, the softer is the pencil. Wood billets of cedar or pine
are cut in half alongside and a groove is cut out for the lead. Both halves of the
pencil are then glued together. The billets are cut into pencils whose surface is
polished. Today more than 300 different kinds of pencils
are produced for various purposes. There are pencils for writing and leaving
trace on such surfaces as glass, fabric,
cellophane, celluloid and plastic, which are used in construction .