Lasico 2000-V Square Root Planimeter with Turntable

This planimeter is designed to find the average of the square roots of all the radial distances from the zero circle to the record line on a circular chart that rests on a turntable underneath the instrument. The planimeter has a 4" green metal angled arm with an adjusting screw and tracer lens; a 6" curved metal arm with a mounting screw and a slotted follower that is inserted in the turntable; and a green metal recording unit with white plastic measuring wheel and vernier and a metal registering dial. The recording unit is marked: LASICO. Underneath the curved metal arm is a serial number: 66607.

The circular white paper chart is marked: Taylor (/) ROCHESTER, N.Y., U.S.A. (/) CHART OP2750 (/) METER ORIFICE (/) TAYLOR INSTRUMENT COMPANIES. The square root symbol is in front of the word CHART. The hours of the day are printed around the outside of the chart. The turntable is black plastic. It is fastened to a white plastic rectangular base. Underneath the base is marked: TURNTABLE 1 06. It is also marked: MADE IN USA (/) MRC R 20 FF.

According to the donor, who worked for the Los Angeles Scientific Instrument Company from 1950 until it closed in 2008, this example was made in 1955 as model 2000-V. It replaced model 125, which had a tracer point instead of a tracer lens. Model 2000-V sold for $550.00 in 1955. For a later example and company history, see 2011.0043.01. The turntable was model 1006 and sold for $225.00.

Taylor Instrument Companies copyrighted the OP2750 chart on June 13, 1933. The firm has a history of selling and making thermometers, barometers, and other instruments that dates back to 1851.

The object was received at the Smithsonian in 2011.

References: Accession file; "The Taylor Story," http://www.taylorusa.com/taylor-about; Library of Congress, Catalog of Copyright Entries . . . for the Year 1933, part 4, n.s., vol. 28, no. 2 (Washington, D.C.: Government Printing Office, 1934).

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