Bresser 40x-640x Bedienungsanleitung Seite 13

fied specimen. At this point, you still might see a slightly fuzzy picture.
Adjust the image sharpness by slowly turning the focus knob (2). You
can now select a higher magnification by turning the objective turret and
selecting a different objective.
When you do so, note that the sharpness of the picture must be adjusted
again for the higher magnification. Also, the higher the magnification,
the more light you will need for good illumination of the picture. The
wheel with pinhole apertures (13) below the microscope stage (4) will
help you in viewing very bright or clear-sighted preparations. Turn the
wheel (13) till the best contrast is achieved.
4. Observation (electronic light source)
For observation with the electronic light source (6) you need to insert
2 AA batteries 1.5 V, in the battery compartment (8) on the base of the
microscope (7). The battery compartment is opened using a Phillips
screwdriver. Insert the batteries with the correct polarity (+/- indication).
Put the battery cover first into the small opening so that the lid fits per-
fectly. Now you can tighten the screw.
The lighting is switched on when you turn the switch on the microscope
base.
Now you can observe in the same way as described in the previous
section.
TIP: The higher the magnification you use the more light is required for
a good illumination of the picture. Therefore, always start your experi-
ments with a low magnification.
5. Condition and prepare viewed objects
5.1. Condition
This microscope features transmitted light, so that transparent speci-
mens can be examined.
If opaque specimens are being examined, the light from below goes
through the specimen, lens and eyepiece to the eye and is magnified en
route (direct light principle).
Some small water organisms, plant parts and animal components are
transparent by nature, but many others require pretreatment — that is,
you need to make a thinnest possible slice of the object by hand cutting
or using a microtome, and then examine this sample.
5.2. Creation of thin preparation cuts
Specimens should be sliced as thin as possible. A little wax or paraffin is
needed to achieve the best results. Put the wax into a heat-safe bowl and
heat it over a flame until the wax is melted. You can use a candle flame
to melt the wax.
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