3. Place the refractive index test glass on the measuring prism surface
with the imprinted side facing up. Position the polished end of the test
glass toward the illuminator - about 1/8" (2mm) from the edge (Figure
4. Align the illuminator so that the light is directed onto the polished
face of the test glass. Cover the illuminator lens with lens tissue to
diffuse the light.
5. Adjust the illuminator arm, dispersion correction wheel, eye-piece
and adjustment control so that the shadowline is centered, in focus,
free of color. This is the same procedure used with a
liquid sample.
6. Depress the READ button and record the digital reading which
appears in the display window.
If the reading differs from the value printed on the test glass by more
than + 0.0001, repeat the measurement several times. Clean the
measuring prism and test glass surfaces with alcohol, followed by
water after each test.
If an error persists, make the following adjustment:
7. Turn the shadow line adjustment control slightly and depress
the READ button. Repeat this procedure until the display agrees
with the test glass value.
The shadowline will now be above or below the center of the
crosshair reticle.
8. Insert the Allen wrench through the reticle access hole in the
dispersion correction wheel. Adjust the reticle until the shadow line
passes through the center of the crosshair (Figure 2 & Figure 3a).
The instrument is now calibrated.
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English