Notes: "This is the 12.5 cm version of Aristo’s Darmstadt slide rule. This one was almost certainly intended for the German market as the instructions are in German. The Darmstadt pattern slide rule is an extension of the earlier Rietz slide rule, adding the P (Pythagorean) scale, a BI scale, and three log-log scales, which are on the back of the slide on this rule."
