Cover of Robert Hooke's publication Micrographia. Hooke details
the manufacture of the microscope he used. He also describes how a short
focus lens is constructed.
In a flame he draws a thin fiber from Venetian glass and melts it into a
tiny bulb, which is then ground and polished.
Within the publication more than 30 detailed drawings appeared including the
famous one from cork that provided the first documentation of a single
cell. When he examined hair he noted that some were split a the ends,
which is quite possibly the first notation for that as well.
An example of the details in the drawings can be seen in the illustrations
below of cork and a flea. It was in his description of cork in
1663 that Hooke first used the term "cork" even though he did not
fully realize how universally important his discovery would become.