Did you know that bread crumbs were used as erasers before the modern eraser was invented? Surprisingly, from 1612 to 1770, bread crumbs were the most popular erasers in the writing world. According to Reader’s Digest, they were able to absorb graphite particles from the paper surface, effectively leaving a clean slate.
But bread crumbs had their drawbacks. They were messy, crumbly, and prone to mold. They also had a tendency to be eaten by hungry writers or animals. That’s why the discovery of rubber as an eraser was a game-changer for the history of writing and drawing.
The story goes that in 1770, an English engineer named Edward Nairne accidentally picked up a piece of rubber instead of bread and found it very effective at erasing pencil marks. He decided to sell natural rubber erasers for the high price of three shillings per half-inch cube, making him the first to market rubber erasers commercially.
However, he was not the first to notice the erasing properties of rubber. That honor goes to Joseph Priestley, a chemist and theologian who is also famous for discovering oxygen. In a footnote to his book on electricity, he wrote: “I have seen a substance excellently adapted to the purpose of wiping from paper the mark of black-lead-pencil. … It is sold by Mr. Nairne, Mathematical Instrument-Maker, opposite the Royal-Exchange.” He called the substance “rubber” because it could rub out pencil marks.
Rubber erasers soon became popular, but they had their own problems. They were perishable and smelly, especially in hot weather. They also left behind black marks and crumbs on the paper. It took another 69 years for someone to solve these issues by inventing vulcanization.
Vulcanization is a chemical process that converts natural rubber and other polydiene elastomers into cross-linked polymers. The most common vulcanization agent is sulfur. It forms bridges between individual polymer molecules when heated with rubber. This makes rubber more durable, elastic, and odorless.
The process was discovered by Charles Goodyear, an American inventor who spent years experimenting with rubber. He accidentally dropped a mixture of rubber and sulfur on a hot stove in 1839 and noticed that it did not melt or burn, but formed a tough and resilient material. He patented his discovery in 1844 and named it after Vulcan, the Roman god of fire.
Vulcanized rubber made erasers more reliable and long-lasting. It also paved the way for another innovation: attaching an eraser to the end of a pencil. This idea was patented by Hymen Lipman, a Philadelphia stationer, in 1858. However, his patent was later invalidated because it was considered a combination of two existing devices rather than an entirely new product.
Today, erasers come in various shapes, sizes, colors, and materials. Some are made from synthetic rubber and soy-based gum, while others are made from vinyl, plastic, or gum-like substances. Some are free-standing blocks or caps that can slip onto pencils, while others are shaped like pencils themselves with retractable cylinders of eraser material.
Erasers are not only used for pencils, but also for pens, chalks, whiteboards, and even digital devices. They are essential tools for artists, students, teachers, and anyone who makes mistakes. And to think that it all started with bread crumbs and rubber!
Relevant articles:
– Was Bread Once Used To Erase Pencil Marks? | Snopes.com, Snopes, Apr 8, 2021
– Eraser – Wikipedia, Wikipedia, accessed on Jan 14, 2022
– The Eraser Was Discovered In 1770. A Pencil With An Eraser Was Invented In 1858…, South Florida Reporter, Apr 14, 2020.