American Telephone and Telegraph Company · (Short Hills, N.J., etc., American Telephone and Telegraph Co.) · leaf 349
POLARIZER ANALYZER LENS LENS Fig. 2.31—A practical conoscope Figure 2.32 shows a cross-section of the Western Electric conoscope. Thegraduated dial shaft goes out through the bottom of the tank to give moreworking room—older instruments had the shaft overhead and it was in theway. The light source… … ^ i^, ^ 250 SPECIFYING QUARTZ CRYSTAL ORIENTATION 251 instead of the 1.546 of quartz. The dial is graduated into degrees and avernier allows readings to tenths of degrees. If a crystal plate is held against the glass reference surface one may readthe angle between the optic axis and the surface…
