Thatcher's Calculating Instrument by Keuffel & Esser Co., New York, No. 4012, 1472, Patd. by Edwin Thatcher, C.E. Nov 1st. 1881, and Divided by W. F. Stanley, London, 1882, with outer paper-covered scales on revolving lacquered-brass rings, and sliding inner cylinder, on mahogany base with paper instruction label, lg. 21 in., in mahogany case with maker's label and 1917 direction manual, (some rubbing on lacquer and case lid ink-stained).