Keuffel & Esser Co. Model 4212 Polar Planimeter, Amsler-Type - 1920

Description

This was my Dad's and is ~100 years old and in very excellent condition. Please see the pictures for details, this is a pre-war German-made K&E Planimeter used to measure areas, a classic tool used by Engineers, Designers, and Draftsman for several generations to measure an area that cannot be easily calculated.
This instrument is made of German silver and has arms of fixed length, with measuring wheels near the vertex of the tracer arm and a carrier for a weight at the end of the other arm. The carrier is marked: KEUFFEL & ESSER Co. The part of the arm below it is marked on the underside: No 4511. The weight is marked: 160. The wooden case is covered with black leather and is lined with blue velvet. The lid is embossed in gold KEUFFEL & ESSER CO. 4212. Keuffel & Esser sold this planimeter as model 1111 from 1892 to 1901 and then as model 4212 from 1901 to 1936. in 1909 the K&E catalog gives a price of .50, these planimeters were apparently manufactured for K&E by a Swiss form established by the mathematician and inventor Jakob Amsler.