3.  The earliest extant example of a mechanical
pencil, also known as an "Eversharp", has been
found aboard the wreckage of HMS Pandora,
which sank in 1791.
 The first patent for a refillable pencil with
lead-propelling mechanism was issued to
Sampson Mordan and John Isaac Hawkins in
Britain in 1822.

4.  The first spring-loaded mechanical pencil
was patented in 1877 and a twist-feed
mechanism was developed in 1895.
 The 0.9 mm lead was introduced in 1938

6.  The mechanical pencil became
successful in Japan with some
improvements in 1915 by Tokuji
Hayakawa, a metal worker who had just
finished his apprenticeship. It was
introduced as the Ever-Ready Sharp
Pencil.

7.  At nearly the same time, in America,
Charles R. Keeran was developing a
similar pencil that would be the
precursor of most of today's pencils.
Keeran's design was ratchet-based,
whereas Hayakawa's was screw-based.
These two development histories are
often combined into one.

8. Mechanism types
Tip of a Ratchet-based mechanical pencil

9. Mechanism types
A Pentel Sharp ratchet draughting pencil disassembled, showing three
0.5 mm graphite leads.

10. Propelling pencil
A Faber-Castell propelling pencil

11. Clutch pencil
A clutch pencil (or leadholder) tends to use thicker
leads (2–5.6 mm) and generally holds only one piece of
lead at a time.