Otis King's Model L Pocket Calculator

Scarce British Otis King's Pocket Calculator, Model "L," a cylindrical pocket slide rule with helical scales No. 429 and No. 430. Patent No. 183723, circa 1921. Designed as a portable mechanical calculating instrument, the telescoping and rotating cylinders employ logarithmic scales for performing multiplication, division, proportions and other mathematical calculations, providing a long effective calculating scale in a compact form. Marked "Otis King's Pocket Calculator" on the scales, stamped "S0903" on one end and "Made in England" on the other. Approx. 6" long closed and 10" fully extended. Includes its fitted leather carrying case and original labeled box. Calculator exhibits light age and handling wear; box and leather case show expected wear from age and storage. Estimate $200 - $300

估價:$200

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