B58-245 FOLDING IVORY ROUTLEDGE ENGINEER'S RULE. James Gargory. Almost all Routledge rules are two fold, two foot boxwood rules designed as working tools for engineers. A handful of folding ivory examples are known, with German silver hinges and 6" slide, which the Reeses suggest was a novelty for gentlemen to carry. This one is very clean, only lightly yellowed and slightly sprung, all markings very clean and crisp. A very uncommon rule. Gargory worked in Birmingham from 1835-1862. Fine 400-800