Hemmi slide rule

Chemical engineering slide rule Maker: HEMMI SLILD RULE CO, Model: 257 Item specifics Condition: Used Ruler is in excellent condition. Country/Region of Manufacture: Japan Item description Hemmi 257 Chemistry Slice Rule.  Celluloid on bamboo.  Duplex.  11 math scales x 25 cm one side; 12 chemical scales other side. The 257 was made from 1952 to 1968 The rule is in excellent condition. Clean and white. Metal parts are clean and bright. The slide and cursor move smoothly and easily. The hard cardboard slip cap case is sturdy.  It has done a good job of protecting the slide rule.