This single sheet of paper was received with 1988.0807.02. It describes how to read the scales for two inexpensive student slide rules, the pocket-sized model 27 and ten-inch model 88, made by the C-Thru Ruler Company of Hartford, Conn. The postal code indicates a date between 1943 and 1963. The back of the sheet is stamped: GEORGE A. NORTON (/) 132 SWANN ROAD (/) WASHINGTON 23, D.C.
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