Proper use of the Compound Microscope 
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Introduction 
Although the light microscope is the most commonly used biological instrument, it is often used improperly. This may not matter so much with very thin commercial slides but proper alignment of the illumination system is essential for viewing thick sections and whole mounts. It is also crucial for photomicroscopy. You will be using microscopes throughout this class and for years to come. If you learn the simple lessons we will teach you today you will do much better in your work and see the exciting world of microscopy in a new light! (Sorry about the pun). The procedure we follow was developed by the German scientist, August Kohler (1866-1948), and it bears his name. Recently his ideas were used to make an advanced Electron Microscope by Zeiss. Thus, this procedure which was introduced in 1893 has been of lasting and value.
The Compound Microscope
Because the lens systems in a
microscope are composed of many lenses it is called compound. The typical illumination of
specimens in which light passes through the specimen and travels to your
eye is called Bright Field microscopy. Light has the
following path.
Eye or Camera
Ocular
Body or Tube
Specimen
Objective
Condenser (Iris)
Condenser Lenses
Field (Iris) Diaphragm
Mirror
Light Source