Mathematical Instruments
Mechanical Instruments for Drawing, Measuring and Integrating
Drafting Instruments
Rechenscheiben und Rechenwalzen
Planimeters and Integrators
Alfred J. Amsler & Co.
Jakob Amsler
Polar Planimeter
Pantograph Planimeter
Amsler
Integrators
Gottlieb Coradi
Hünenberger-Murbach
Various Makers