Page:US patent 1682572.pdf/4

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

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