NANOTECHNOLOGY—TECHNOLOGY ON A MOLECULAR SCALE - Chemistry: Notable Research and Discoveries - page 36

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N ANOTECHNOLOGY —
T ECHNOLOGY ON A
M OLECULAR S CALE
Th e Dutch craft sman Antoni van Leeuwenhoek (1632-1723) built some
of the fi nest microscopes available in the 17th century. Th e quality of a
microscope depends on the quality of the lens or lenses it uses to bend
light and form an image. Leeuwenhoek's microscopes contained a single
lens, and this lens was so carefully made and ground into the correct shape
that his instruments were superior to most others. When he used the mi-
croscope to peer into drops of water, Leeuwenhoek was amazed to see tiny
swimming creatures.
Leeuwenhoek and other early microscopists unveiled a new branch of
science with the discovery of microorganisms and other tiny objects, invis-
ible to the unaided eye. Yet scientists of the 17th and 18th centuries did not
understand this new, miniaturized world. Th ey had a tendency to describe
and think about these objects as if they were tiny replicas of larger, more
familiar objects. For instance, Leeuwenhoek and fellow Dutchman Nicolas
Hartsoeker (1656-1725) took this attitude when they studied male repro-
ductive cells called semen. Th ese little cells, when united with female re-
productive cells called ova, initiate an amazing and complex developmen-
tal process by which the cells grow, divide, and become a human being.
But this process was unknown in the 17th century. When Leeuwenhoek
and Hartsoeker examined semen, they thought they saw a tiny version of
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