The Invention Of Erasers

History Behind Erasers

Before rubber erasers, tablets of rubber or wax were used to erase lead or charcoal marks from paper. Bits of rough stone such as sandstone or pumice were used to remove small errors from parchment or papyrus documents written in ink. Crust less bread was used as an eraser in the past; a Meiji-era (1868-1912) Imagine a bread used for rubbing pencil marks today.

A Tokyo student said: "Bread erasers were used in place of rubber erasers, and so they would give them to us with no restriction on amount. So we thought nothing of taking these and eating a firm part to at least slightly satisfy our hunger."

On April 15, 1770, Joseph Priestley described a vegetable gum to remove pencil marks: "I have seen a substance excellently adapted to the purpose of wiping from paper the mark of black lead pencil." He dubbed the substance "rubber".

In 1770, Edward Nairne, an English engineer, is credited with developing the first widely-marketed rubber eraser for an inventions competition. He sold natural rubber erasers for the high price of three shillings per half-inch cube. According to Nairne, he inadvertently picked up a piece of rubber instead of breadcrumbs, discovered rubber's erasing properties, and began selling rubber erasers. Incidentally, that was the first practical application of the substance in Europe, and rubbing out the pencil marks gave it its English name.

However, raw rubber shared the same inconveniences as bread, since it was perishable. It was noticed that while the rubber softened in warm weather, it became hard in cold conditions. What 's more, the first rubbers had an unpleasant smell if you kept using it. A scientist named Charles Goodyear invented the process of 'vulcanization' in 1839. This innovative process enabled rubber to become more long lasting, elastic and more durable in nature. Rubber erasers became common with this advent of vulcanization.

On March 30, 1858, Hymen Lipman of Philadelphia, USA, received the first patent for attaching an eraser to the end of a pencil. It was later invalidated because it was determined to be simply a composite of two devices rather than an entirely new product.

How an eraser makes everything disappear

Ever wondered how all these materials erase graphite, charcoal and lead marks on paper? The logic behind it is quite simple. The molecules in erasers are relatively stickier than those constituting paper. Therefore, when an eraser is rubbed onto a pencil mark, the graphite sticks to the eraser's surface instead of the paper's surface. While it does this, the eraser can damage the top layer of the paper itself if used too roughly. It leaves some residue on the paper, which then needs to be removed. Erasers are primarily adsorbents.