In prehistoric times, lumps of colored earth or chalk were used as markers. The so-called lead pencil—a rod of graphite encased in wood—first came into use in the 16th century. However, it was not until the 19th century that the eraser was added—an innovation that earned Hymen Lipman a patent in 1858. In 1862, he sold his patent to Joseph Reckendorfer for $100,000. What happened to Reckendorfe’s patent 13 years later? Discuss
Source: The Free Dictionary