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. Pencils got their name from the old English word meaning 'brush'. Conte's method of kiln firing powdered graphite and clay allowed pencils to be made to any hardness or softness - very important to artists and draftsmen.
Source:http://inventors.about.com/library/inventors/blpen.htm
Walang komento:
Mag-post ng isang Komento