K+E Keuffel & Esser COMPENSATING POLAR PLANIMETER Drafting Cartography Tool 1938 Made in Germany, Model 4236. This is the first model.  Includes original instruction manual with illustrations (16 pages), Inner case lied in velvet (very good), outer cardboard case (intact but very worn around the edges).  The instrument appears unused or with little use. The Compensating Polar Planimeter was/is used to measure distances on maps and measures the area of a region by tracing the boundaries.  Excellent condition.