Mechanical pencils have gone through a lengthy period of innovation.
Mechanical pencils have a long history throughout the United States, Europe and Japan. Developments in how the lead is advanced in the pencil and lead diameter have occurred throughout the last century to result in today's mechanical pencils.
History
Two British men, Sampson Mordan and John Isaac Hawkins, obtained the first patent for a mechanical pencil with refillable lead in 1822. The modern mechanical pencil most resembles the models being developed in Japan and the United States beginning around 1915.
Types
Ratchet-based mechanical pencils have lead that is held at the pencil's tip, and is then propelled out of the pencil by a button on the body or at the end of the pencil. This is the most popular type of mechanical pencil.
Features
Some mechanical pencils are disposable; when the lead is gone, the rest of the pencil is thrown away. Most are refillable; lead diameters in most modern-day mechanical pencils range from 0.3mm to .9mm.
Fun Fact
The earliest known version of a mechanical pencil was found in the wreckage of HMS Pandora. This ship sank in 1791 and was the vessel that pursued Captain William Bligh's HMS Bounty after its crew's mutiny.
