Slide rule in leather case -- Keuffel & Esser Co #4081-3, 1940s $8.99 USD Sold on: 2013-Dec-27 Marketplace: eBay ![]() 1 Treasure 0 Trash ![]() ![]() Classic Keuffel & Esser Log Duplex DeciTrig slide rule. The latest patent dates from 1940, and Mr. Lundin was already a graduate student in Chicago by 1950, so the timeline for dating this is pret... ![]() More Relevance Historical Items
|