Mader-Ott Harmonic Analyzer
date: label: date made
content: 1931
name: label: maker
content: Ott, Albert
notes: label: Description
content: A harmonic analyzer is a mechanical instrument for reducing a curve to its expression as a Fourier expansion. It calculates the coefficients to be used when the curve is expressed as the sum of a series of sines and cosines. In 1909, the German engineer Otto Mader introduced this form of harmonic analyzer, which used a set of wheels to find successive coefficients for the expansion of a plotted curve. This version of Mader’s invention was made the firm of A. Ott in Kempten, Germany.
label: Description
content: The wooden box, 34 ¾” wide x 27” deep x 3 ¼” high contains the following components:
label: Description
content: 1. A triangular carriage, measuring 18” x 12” with three wheels. This contains a smaller triangular carriage with a rack as well as a plate with holes for inserting gear wheels. A mark on the gear wheel plate reads: A. Ott, Kempten, no. 2253. A mark on the bottom reads: 5650A. A mark on the bottom of the smaller carriage reads “2”. Another mark there reads: A. Ott Kempten.
label: Description
content: 2. Some 108 brass gear wheels (two sets of 54), the smallest 5/8” in diameter and the largest 3 1/8” in diameter.
label: Description
content: 3. A tracer arm, 26 ½” long, graduated in tenths from 2 to 73. A pivot is at one end and a guide knob controlling the height at the other. Attached are a moveable tracer pin as well as a rotating lever. The lever is 7 ¾” long with a pivot at the other end.
label: Description
content: 4. A guide rail, 28 3/8” x 1 ¾”, graduated from 0 to 36. It has one groove, two notches, and two holes for fastening pins.
label: Description
content: 5. A lever 15” x 8 ¼” x 16 ½”. The first side is a tracer arm graduated from 2 to 37 in tenths that contains a moveable tracer pin, ball pivot, and guide knob like (3).
label: Description
content: 6. A triangle, 11 ½” x 11 ½” x 5 ¾”. It has one wheel, two ball pivots, and one hole; and is stamped “2” on the bottom.
label: Description
content: 7. A guide rule, 17 ¼” long, with a grooved piece 5 ½” long attached at the left end. It is stamped on the bottom: 29. The grooved piece is graduated in tenths with the zero-point at the center, and runs from 0 to 37 in both directions. A second set of readings runs from 0 to 36 using the same scale reading from +36 to -36 of first set.
label: Description
content: 8.Two brass and steel compensating polar planimeters, both marked: A. Ott Kempten. One is also marked with a serial number “No. 49475”, the other “No. 49476”. Each consists of a tracer arm, 7” long, attached to a plate containing a measuring roller and counter, and a pole arm, 8 ¾” long with pole.] Each planimeter has a pole plate and a control rule 4” long. Each planimeter also has a screwdriver (a metal piece ¾” x ¾”) for replacing the pivot point. Both planimeters are in black wooden cases that measure 10 ½” x 3 5/8” x 1 ¾”. A listing of constants in German is pasted inside the case.
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content: 9. A wooden base, 19 ¾” x 10 ¼” x 1 ¾”.
label: Description
content: Unless indicated otherwise, the components are made of steel with chrome and aluminum finish.
label: Description
content: References:
label: Description
content: NMAH Accession file 254098.
label: Description
content: Detlef Zerfowski, “Calculating Waves Not only on the Beach, Mechanical Calculation of Harmonic Waves by Harmonic Analyzers,” <I> Proceedings of the 25th International Meeting of Collectors of Historical Calculating Instruments, September 20th to 22nd, 2019</I>, The Hague & Scheveningen, The Netherlands, pp. 191-210. See https://www.zerfowski.com/Papers/Zer2019-1_Calculating_Waves.pdf , accessed September 1, 2020.
label: Description
content: Compare the example at the Science Museum, London – see https://collection.sciencemuseumgroup.org.uk/objects/co60186/harmonic-analyser-maders-form-in-fitted-case-harmonic-analyser-planimeter, accessed September 2, 2020.
label: Location
content: Currently not on view
place: label: place made
content: Germany: Bavaria, Kempten
topic: label: Subject
content: Mathematics
setName: label: See more items in
content: Medicine and Science: Mathematics
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content: Mechanical Integrators and Analyzers
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content: Science & Mathematics
creditLine: label: Credit Line
content: Transfer from U.S. Naval Weapons Laboratory
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MA.324276
label: catalog number
content: 324276
label: accession number
content: 254098
objectType: label: Object Name
content: harmonic analyzer
physicalDescription: label: Measurements
content: overall: 8.2 cm x 88.3 cm x 68.6 cm; 3 7/32 in x 34 3/4 in x 27 in