Amsler type planimeter with fixed index
An amsler type polar planimeter with fixed index, in original velvet-lined box, was used for measuring areas on drawings and maps. C 1890. The irregular outline of an area is followed by a tracing point causing motion to the mechanism and the computation is arrived at by multiplying the reading recorded on a graduated wheel by a given factor. Invented by j amsler professor of mathematics schaffhausen in 1854. Dimension case 22 x 5 x 4cm.