<div class="description">
<p>Original illustration used for Figure 9. Minimum spectral band widths which permit scale readings to 0.1 percent from  from  Cary, H. H.; Beckman, Arnold O. (1941). "A Quartz Photoelectric Spectrophotometer". <i>Journal of the Optical Society of America</i>. 31 (11): p. 688. doi:10.1364/JOSA.31.000682. 
</p><p>No copyright renewal for the journal (first renewal appears for 1951).
No copyright renewal for the paper.
</p>
No copyright renewal for the photograph (checked 1968, 1969).</div>
<div class="fn value">
Unknown<span style="display: none;">Unknown </span></div>
1941<div style="display: none;">date QS:P571,+1941-00-00T00:00:00Z/9</div>
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