/kloc-In the 6th century, the British began to use graphite strips. At first, it was mainly used by merchants to mark commodities, so people called it "Yin Shi". According to legend, "Yin Shi" was discovered by a shepherd.
1564, a violent hurricane hit the Cumberland Plain in England. After the storm stopped, a shepherd drove his sheep past a big tree. He went to the root pit curiously and found a big black stone exposed in the pit. "Strange, what is this?" So, he jumped into the pit and used his hand to mold "Blackstone", and his hand was immediately dyed black; As a nail struck, a trace appeared on the Blackstone. This black and soft "stone" has never been seen before.
Looking at his pair of black hands, the clever shepherd suddenly thought: use it to mark his flock, so that his flock will not be mistaken. He quickly picked a lot of "Blackstone" to take away. Because this kind of "black stone" is like lead, it will make things that come into contact with it black, so shepherds call it "black lead".
Later, a shrewd businessman saw "black lead" and decided that there was money in it. At that time, Britain's trade was developed, and businessmen needed to mark numbers and write on the packaging bags of goods, but businessmen have been suffering from the lack of ideal writing tools. Businessmen dug up "black lead", cut it into strips, wrapped it in cloth, labeled it and sold it to businessmen.
In fact, this "black lead" is graphite. Compared with a real pencil, its handwriting is bold and black, and the effect is much better. Therefore, this kind of "Yin Shi" business is booming, and the whole ship of "Yin Shi" has crossed the English Channel and been transported to the European continent, which has almost become an indispensable commodity in the trade of various countries.
After using "Yin Shi" for a period of time, people found its inconvenience: the handwriting is too black and easy to fall off; A little hard, it will break; It is also easy to get dirty when writing. How to overcome these defects of "Yin Shi"? Until the18th century, the German chemist Faber grasped this difficulty.
Faber believes that to improve graphite, it is necessary to grind it into powder and then bond it with something, so as to achieve the goal. According to this idea, he conducted repeated experiments and found that improved graphite can be obtained by mixing a certain amount of sulfur antimony and rosin into graphite powder and heating and curing. Moderate hardness, smooth writing, clear handwriting, not easy to get dirty hands. In order to protect the pen core, Faber also wrapped the lead core with a piece of paper. Thus, a new type of pencil was born.