Modern instruments and methods of calculation : a handbook of the Napier Tercentenary Exhibition (1914)
Horsburg, E. M. (Ellice Martin), Napier Tercentenary Exhibition (1914 : Edinburgh, Scotalnd) · London : G. Bell · leaf 237
Fig. 3. With the ordinary polar planimeter there is a possible source of error,due to the axis of the recording wheel not being parallel to the tracer arm.In order to eliminate this error, if present, it is necessary to take the mean … >*r Fig. of two readings from an area, one with the pole to the left of the tracer arm,the other with the pole to the right, as indicated in rig. 4. With the Amslerplanimeter this cannot be done. The tracer arm is mounted above the polearm, and so the range of the tracing point is restricted.…
