(a) Sight on the object whose temperature is to be measured and adjust
the focus knob for the sharpest image.
(b) Close the contacts by pressing the switch, which is located on the
lower right side of the telescope sight piece.
(c) Rotate the knurled knob until the filament of the lamp blends with
(has the same brilliance as) the image of the hot object (until an optical balance
(d) In making the optical balance, use the section of the lamp filament
which is opposite the index of the lamp.
(e) Move the telescope from the line of sight, keeping the switch
closed, and press in on the knob which is located on the lower left-hand corner of
the front panel.
While holding the knob in, rotate it until the galvanometer
pointer balances at zero on its scale.
(f) Read the value of temperature (on the proper scale).
(4) We hope that you included the processes of reaching an optical balance
and adjusting the galvanometer pointer for a zero balance in your determination of
the measurement principle.
When the processes mentioned are performed, the
intensity of light from the source whose temperature is to be measured equals the
intensity of light from the standard source; the