12
piece into position and place the installed
1.6X
objec
tive into the optical path, using, to this end, rod
(19).
for illumination, use is made of the low-power condenser.
For this purpose, move condenser
0.95
down1111ard after press
ing lever
(7),
and swing it to the left. Completely open
field and aperture diaphragms.
8.
The analyzer is arranged
slide with three light passages.
It is IJIIithin the optical path when the analyzer rotations
control
{)9)
is at a position next to the tube. At the
slide's mid-position the angle is read. To this end, it
is necessary to engage the detent by pulling out and turn
ing lever
(41),
and to swing the Bertrand lens into the
optical path by means of rotary knob
(20)
and to focus
onto the scale by shifting knob
(20).
The slide's third
position permits the free passage of the imaging rays. If in
this position the image should be too bright for observation,
it is possible to introduce an attenuation filter into the
optical path by means of slide
(1).
Tho r-otary knob of this
filter is connected with an arresting lever. Turning the
knob to the right causes the lever to be swung out, so that
the filter slide can be removed from the analyzer slide. As
required by the user, the brighter attenuation filter d
(recommended for transmitted light) or the darker one a
(recommended for incident light) may be inserted into the
free aperture. lf analyzer and polarizer are positioned at
"0"
1
the vibration planes of the respective light passing
through
vertical to each other: the polars are crossed.
9.
foe observing interference figures the Bertrand lena is
switched into the optical path by means of rotary knob
(20)
and focusseQ onto the ap�rture diaphragm. field
diaphragm ond tube iris diaphragm ore closed as much as
required. Polarizer and analyzer are positioned at
"011•
The aperture diaphragm is completely opened. for photo-
