RARE WHITE ON BLACK OTIS KING PATENT CALCULATOR MODEL K
09-037. English, early 2nd quarter 20th century, signed "Otis King's Pocket Calculator." The spiral logarithmic scales No. 423 and No. 414, both with a white scale on a black background, are mounted on two chrome plated metal tubes, while a third chrome plated metal tube is mounted on the holder to form a tubular cursor, carrying at each end an engraved arrow or pointer which can be set at any mark. This rare early Otis King Patent Calculator variation is in very good overall condition, in its original fitted case. A Xerox copy of the original instruction booklet is also included.
