Page:US patent 1682572.pdf/3

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 * Aug. 28, 1928.
 * 1,682,572
 * 1,682,572

OPTICAL INSTRUMENT
 * Filed Oct. 15, 1925
 * 4 Sheets&mdash;Sheet 3
 * }
 * Filed Oct. 15, 1925
 * 4 Sheets&mdash;Sheet 3
 * }