Double Slide Rule (dated 1815), inscribed on one side EXCHANGES BULLION ETC; PULISHED BY W.CARY - 182 STRAND, APR.1.1815; on other side WEIGHTS AND MEASURES AND COINS; PUBLISHED BY W. CARY - 182 STRAND, APR.24.1.1815. Printed on paper, varnished and mounted on mahogany Double Slide Rule (dated 1815) 1815-1820
