Summarize the invention of pencil

1564, a black mineral-graphite was discovered in a place called barodale, England. Because graphite can leave traces on paper like a ship, which is much darker than the traces of lead, people call graphite "black lead". At that time, shepherds in Barodale often used graphite to mark sheep. Inspired by this, people cut graphite blocks into small strips for writing and painting. Soon, King George II of England simply owned the Barodale graphite mine to the royal family, making it an exclusive product of the royal family. Writing with graphite strips is easy to get dirty and break. 176 1 year, the German chemist Faber first solved this problem. He washed graphite with water to make it into graphite powder, then mixed it with sulfur, antimony and rosin, and then made this mixture into strips, which were much tougher than pure graphite strips and not easy to get dirty. This is the earliest pencil. Until the end of18th century, only Britain and Germany cut off the supply of pencils to France. So Britain and Germany cut off the supply of pencils to France after Napoleon launched a war against neighboring countries. Therefore, Napoleon ordered the French chemist Comte to look for graphite ore in his own country and then make pencils. However, the quality of graphite ore in France is poor and its reserves are small. Comte mixed clay into graphite and put it in a kiln for barbecue, which made a good and durable pencil lead in the world at that time. Pencil lead hardness and color depth produced by different clay proportions in graphite are different. This is the origin of H (rigid pencil), B (soft pencil) and HB (pencil with moderate hardness) marked on today's pencils. The task of putting a wooden stick coat on a pencil was completed by American craftsman Monroe. He first built a machine that could cut the battens, then carved a slot in the battens, put pencil lead in the slot, and then aligned and glued the two battens, with pencil lead tightly embedded in the middle. This is the pencil we use today.