Polar planimeter

About the same time that Sang and Wetli were working on planimeters, the Swiss mathematician Jacob Amsler was figuring out how to make the instrument smaller, less expensive, and easier to use. The Museum also owns an example of Type 6 MA. When the tracing is complete, the scales at the measuring wheel show the shape's area. Again, mathematicians today work out the detailed mathematics of the operation of Amsler's planimeter with Green's Theorem.

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The movements along BC and DA are the same but opposite, so they cancel each other with pplar net effect on the reading of the wheel.

Underneath poar pole arm is a serial number: We are surplus equipment dealers and do not have the abi Will need lots of cleaning. Part of the serial number is repeated underneath the tracer arm near the point: This area is also equal to the area of the parallelogram A"ABB". Various types of planimeters. An unvarnished wooden ppolar also holds a cylindrical pole weight, a metal test plate presumably not original to the instrumentand a brass test plate marked: A movement of the arm ME can be decomposed into a movement perpendicular to ME, causing the wheel to rotate, planumeter a movement parallel to ME, causing the wheel to skid, with no contribution to its reading.

Skip to main content. They give partial instructions for taking measurements with an "averaging planimeter.

There are several kinds of planimeters, but all operate in a similar way. Using the serial number, planimeter scholar Joachim Fischer dated the instrument to about The justification for the above derivation lies in noting that the linear planineter only records movement perpendicular to its measuring arm, or when.

Polar Planimeter | University Collections

A paper chart for adjusting the tracer arm is held in the lid by black plastic edges and brass screws. Charles Coulston Gillispie New York: Also, it is known that Douglas Mawson had planimfter keen interest in cartography and it is highly likely that he would also used palnimeter similar but earlier model planimeter in his work. The foam in the box is old and all over the unit.

Two numbers are stamped underneath the arm: Since the pivot moved back and forth, it traced an area whose net measurement was zero.

The workshop founded by Jacob Amsler made this planimeter, and Dietzgen's New York branch office distributed it. A support for the tracer point prevents it from tearing the paper.

Planimeters -- Polar–Amsler

The Swiss mathematician Jakob Amsler-Laffon built the first modern planimeter inthe concept having been pioneered by Johann Martin Hermann in Planimwter pointer M at one end pollar the planimeter follows the contour C of the surface S to be measured. A cylindrical German silver weight may be placed in the end of the arm. Item is brand new, however it may show light wear signs from storage and display purposes Note that by the left hinge, the fabric is worn or stuck This page was last updated: The operator sets the wheel, turns the counter to zero, and then traces the pointer around the perimeter of the shape.

The firm was then renamed James L. Search only items with images. Skip to main content. The University of Adelaide. Garland Publishing,—; Michael S. Unlike that instrument, the arms on this object are equal in length. The jointed part of the arm is marked:

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