serial number 2048, signed 'A Ott, Kempten, Bayern', in fitted case with instructions and additional notes regarding the mathematical theory, case width 63cm, with a universal or combination planimeter by A Ott, complete with accessories in velvet lined case, case width 25cm; Notes: This mechanical Fourier analyser (an analogue computer or integrator) is used in conjunction with a planimeter. The design is attributed to O. Mader, and the instruction booklet (in French) is entitled L' Analyseur Harmonique Mader-Ott. The accompanying universal planimeter can be used as a linear, polar, or radial planimeter. Reference: Notes on Mechanical Fourier Analyzers, Robert K Otnes, Journal of the Oughtred Society Vol 17 No. 1 2008