Polarizing light microscopes are expensive. The cheapest are several thousand
dollars. They are delicate instruments which work best when kept aligned
and dust free. Consequently, it is important to take very good care of
the microscope you are using. If it seems to be out of alignment or dirty
resist the temptation to twiddle the knobs or clean it. Consult your instructor
for assistance.
Below are some important guidelines for use of the microscope.
1. Focus using the lowest power of magnification first, then increase magnification.
2. Know which way the focusing knob turns to raise and lower the stage,
it is important not to smash your sample into an objective. Not only may
your sample be ruined but the several hundred dollar objective may be damaged.
A good rule of thumb is to set the minimum separation between the objective
and the slide by external inspection and then focus by lowering the stage
away from the objective.
3. Use only lens paper (with a puff of breath for moisture if necessary)
to clean optical surfaces.
4. Never use the polarizing light microscope for microchemical testing.
The acids and other chemicals are corrosive.
5. Anytime a piece of the microscope is removed (ie., an objective) it
should be immediately placed in its storage container and the resulting
opening sealed to prevent dust from collecting inside the microscope.
6. When finished, the microscope must be covered with its plastic cover
again to keep out dust.
7. To preserve the lamps always turn the microscope on, then increase the
intensity to the desired level. When finished first decrease lamp intensity,
then turn the power off.