Microscope History
"Microscopes are devices by which one can make visible details of
structure too minute to be seen by the unaided eye, or too poorly
differentiated from their surroundings to be identified."(1)
The first record of the use of lenses to manipulate images was in
Greek and Roman writings of around 1000 A.D. (2) As
for the origins of someone using lenses to magnify a minute object, it is
unclear. Most scientific instruments have a clear place in the historical
records when they were formed and who created them, not the microscope
though. The definition of the microscope makes it difficult to determine
when it was first created. Since there were lenses dating back to ancient
societies, how do we say when those lenses were used to look at minute
objects? It is practically impossible to say when a single lens was used
in that fashion. Credit for the first compound microscope (multiple
lenses) is generally given to Zacharias Jansen and John Lipperhey of the
Netherlands, in 1590.(3)
It is likely that the microscope was a result of work made on the
telescope. The telescope had much more practical uses in that time,
because it could be used for maritime navigation.(4)
"The telescope was a deliberate invention, but the microscope
was discovered; an accidental action of the telescope exhibited a property
irrelevant to its main purpose, but which could be exploited and developed
by someone with the wit to recognize it and its possibilities."(5)
This idea is supported by the account
of one of the first compound microscopes, which was six feet long and had
a one inch barrel with a lens at either end.(6)
After the compound microscope the next major development was in
lenses. Half a century after the compound microscope, both Anthony van
Leeuwenhoek and Robert Hooke realized that lenses with very short focal
lengths was the key to more magnification. This meant the use of
extremely double convex or spherical lenses.(7) They
also used lenses made of pure quartz, creating a more pure glass instead
of the poor quality, greenish glass of the day.(8)
The problem of making lenses in this fashion was that it created chromatic
aberration.(9) This aberration is because different
wavelengths of light are refracted different amounts, resulting in a
smeared image instead of a clear one.
In 1758 John Dollard patented an achromatic lens. Even with this new
lens, it was not until 1930 when Lister was able to use it to alleviate
the problem of chromatic aberration.(10) Much of the
interim time was spent on telescope technology.
Another form of the microscope, first proposed by Isaac Newton in
1692, is the reflecting microscope. In this case the light would not
pass through a lens, but would reflect off of a concave mirror. Since
all light is reflected the same, there would be no problem with
chromatic aberration. The first reflecting microscope was made by
Barker in 1736. This model was developed directly from reflecting
telescope designs. Reflecting microscopes are used today, but the
transmision type are much more prevalent.(11)
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