B64-742. INCLINOMETER RULE. W.F. Stanley. These folding rules, with level vials in both legs, sights on the top leg, and a compass, were widely produced by a variety of instrument makes in the nineteenth century, primarily in England. We've seen them called "gentlemen's" rules or compendia. This one is by famed London instrument maker W.F. Stanley and is in mint, unused condition in its original plush-lined leatherette box. From the collection of Chuck Morgan. Condition: Fine, Estimate: 350-700