Editing Cell theory (section)

== Microscopes==

{{Further|Microscope#Rise of modern light microscopes}}

The discovery of the cell was made possible through the invention of the microscope. In the first century BC, Romans were able to make glass. They discovered that objects appeared to be larger under the [[glass]]. The expanded use of lenses in [[eyeglasses]] in the 13th century probably led to wider spread use of [[Optical microscope#Simple microscope|simple microscopes]] ([[magnifying glass]]es) with limited magnification. [[Optical microscope#Compound microscope|Compound microscopes]], which combine an [[Objective (optics)|objective lens]] with an [[eyepiece]] to view a [[real image]] achieving much higher magnification, first appeared in Europe around 1620. In 1665, Robert Hooke used a microscope about six inches long with two convex lenses inside and examined specimens under reflected light for the observations in his book ''[[Micrographia]]''. Hooke also used a simpler microscope with a single lens for examining specimens with directly transmitted light, because this allowed for a clearer image.<ref name=Gest/>

An extensive microscopic study was done by [[Anton van Leeuwenhoek]], a draper who took the interest in microscopes after seeing one while on an apprenticeship in Amsterdam in 1648. At some point in his life before 1668, he was able to learn how to grind lenses. This eventually led to Leeuwenhoek making his own unique microscope. He made one with a single lens. He was able to use a single lens that was a small glass sphere but allowed for a magnification of 270x. This was a large progression since the magnification before was only a maximum of 50x. After Leeuwenhoek, there was not much progress in microscope technology until the 1850s, two hundred years later. [[Carl Zeiss]], a German engineer who manufactured microscopes, began to make changes to the lenses used. But the optical quality did not improve until the 1880s when he hired [[Otto Schott]] and eventually [[Ernst Abbe]].<ref name="Unifying Concept"/>

Optical microscopes can focus on objects the size of a [[wavelength]] or larger, giving restrictions still to advancement in discoveries with objects smaller than the wavelengths of [[visible light]]. The development of the [[electron microscope]] in the 1920s made it possible to view objects that are smaller than optical wavelengths, once again opening up new possibilities in science.<ref name="Unifying Concept"/>

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File:Leeuwenhoek Microscope.png|A reproduction of Anton van Leeuwenhoek's 17th century microscope with magnification of up to 300x<ref name=funsci>{{cite web |url=http://www.funsci.com/fun3_en/usph/usph.htm |title=A glass-sphere microscope |publisher=Funsci.com |access-date=13 June 2010 |archive-url=https://web.archive.org/web/20100611200259/http://www.funsci.com/fun3_en/usph/usph.htm |archive-date=11 June 2010 |url-status=dead }}</ref>
File:Hooke-microscope.png|Robert Hooke's microscope setup, as depicted in ''Micrographia''
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