Amsler Type 2 Polar Planimeter Sold by Dietzgen

This fixed-arm polar planimeter has a 4-1/2" tracer arm and 7" pole arm with cylindrical weight. It is made of German silver with a gold-colored coating. The tracer arm and pole arm are connected by a hinge and form a circle around the white plastic measuring wheel and vernier when the instrument is closed. The planimeter does not have a registering dial. The pole arm is marked: Eugene Dietzgen Co. New York Swiss Manufacture. A serial number is underneath the tracer arm: 57202.

A wooden case is covered with black leather and lined with black velvet. Three labels are glued to the bottom of the case. The edges of the first are torn away, but it reads: Made in Switzerland. The second is a white inventory tag marked: TULANE UNIVERSITY (/) 74 2281. The third is tape marked: 3.

The workshop founded by Jacob Amsler made this planimeter, and Dietzgen's New York branch office distributed it. Using the serial number, planimeter scholar Joachim Fischer dated the instrument to about 1920. In 1926, Dietzgen sold an Amsler Type 2 planimeter without registering dial as model 1800 for $17.75, although the catalog showed the instrument as having a short third arm that held the pole weight. Compare to MA.318485, 1984.1071.01, and 1989.0305.01. Mechanical engineering faculty R. M. Rotty and E. H. Harris arranged for the donation of this planimeter in 1964.

References: Joachim Fischer to Peggy A. Kidwell, October 19, 1992, Mathematics Collection files, National Museum of American History; Catalog of Eugene Dietzgen Co., 12th ed. (Chicago, 1926), 180; N. Hawkins, Hawkins' Indicator Catechism (New York: Theo. Audel & Co., 1903), 122–123.

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