What are more common than pencils in our stationery? However, how much do you know about pencils?
Old pen of aluminum pen
The pencil originated in ancient Greece and Roman times more than 2,000 years ago. The pencil at that time was very simple, except that there was a lead in the metal sleeve, and it could even be a block. But from the point of view of words, it is a veritable "pencil." The pencil refills we use today are made of graphite and standing soil and are lead free.
Pencil is born
Speaking of pencils, I have to mention graphite with the name "black lead". In the 16th century, Barrowdale, people discovered a black mineral, graphite, which is often used by local sheep to mark the sheep. It not only leaves marks on paper, but also The traces left by lead are still black. Then graphite is called "black lead." Later, people cut the graphite block into small strips, wrapped in string or parchment, and used to write letters.
Unfortunately, writing with graphite strips not only stains the hands, but also breaks easily. In 1761, the German chemist Faber decided to solve this problem. He washed the stone with water, turned the graphite into graphite powder, then asked the sulphur building, the cake, the rosin to mix, and then heated the mixture to form a pen shape. This is the earliest dimension of the pencil. This pencil is not only more resilient than pure graphite strips, but also does not easily stain the hands.
Artists make contemporary pencils
Soon, the pencil was widely spread because of its usefulness, and it attracted the attention of artists all over the world. They found it very convenient to draw with a pencil, so a series of modifications were made to the pencil.
First of all, Italy came to think of fixing it with wood. They dug out the stick-like run in the wood and put on the refill. After a while, people invented a more simple way: use two pieces of carved wood to hold the stone mold stick, and then glue the two pieces of wood together with glue - essentially, this method The making of the pencils used today is one-effect.
do you know? Napoleon also made a great contribution to the appearance of pencils! At the end of the 18th century, only the United Kingdom and Germany were able to produce such pencils. When Napoleon launched a war against neighboring countries, Britain and Germany no longer supplied pencils to France. He was very annoyed and ordered chemists to transfer graphite mines on their own land and then make pencils.
Due to the poor quality of the graphite mines in France and the small amount of reserves, the living chemist Kongde mixed the graphite powder with the earth, made it into a rod shape, and then put it into the kiln for roasting, which made the world look good at the time. Durable pencil lead, this method of production has been used today.
Comte also found that by changing the ratio of graphite to clay mixing, you can change the break of the graphite rod! The more clay, the harder the pencil and the lighter the pen speed.
