Koenig harmonic analyzer with manometric flames
Date: circa 1865
Inventory Number: 1998-1-1606
Classification: Manometric Flame Apparatus
Subject:
Maker: Rudolph Koenig (1832 - 1901)
Place of Origin:
Dimensions:
90.2 × 81.3 × 39.4 cm (35 1/2 × 32 × 15 1/2 in.)
Description:
This instrument consists of eight Helmholtz spherical resonators (two missing) mounted vertically in a cast iron frame. Adjacent to the resonators is a wood distribution box with eight manometric capsules (one for each resonator). The capsules were connected by rubber tubes to their paired resonators, but the tubing has hardened and broken into pieces; it is no longer attached. The manometric capsules each have a brass nozzle with a stopcock through which a gas would enter. On the other side of the distribution box, there are eight nozzles where the gas flames would come forth.
Near the distribution box is a large rectangular box made of wood and originally covered with four mirrors (now missing). It is mounted vertically on an inclined spindle and made to rotate by a hand crank and gearing.
Resontaors are each marked with the "RK" monogram near their large openings. Each is also marked (largest to smallest) UT 4, UT 3, MI 4, 6, 7, 8.
Near the distribution box is a large rectangular box made of wood and originally covered with four mirrors (now missing). It is mounted vertically on an inclined spindle and made to rotate by a hand crank and gearing.
Resontaors are each marked with the "RK" monogram near their large openings. Each is also marked (largest to smallest) UT 4, UT 3, MI 4, 6, 7, 8.
In Collection(s)
SignedRUDOLPH KOENIG À PARIS
on each resonator, stamped: RK
on each resonator, stamped: RK
Inscribedon sticker: 19-6-2
stamped in ink: 20-14
stamped in ink: 20-14
FunctionThis instrument is an ingenious method devised by Rudolph Koenig to visualize and analyze sound frequencies.
When the air in a resonator vibrates, the vibration is transmitted through a rubber tube to a manometric capsule. The vibrating rubber membrane in the capsule modulates the flow of gas feeding a flame, causing it to vibrate, too.
The motions of the flames are too rapid to be perceived by the eye directly. However, by observing the flames in rotating mirrors, the flames appear as sawtoothed bands or strips of light. This is due to the persistence of the image on the viewer's retina. The flame of an excited resonator produces a saw-toothed image in the mirror. The flame of an unexcited resonator produces a luminous stripe without teeth.
By examination of the flames, one can determine the frequencies that combine to make up a compound sound. Koenig's harmonic analyzer, therefore, is like a Fourier analysis, in finding a combination of frequencies that compose a given sound.
This method of analyzing sound frequencies were widely used until the beginning of the 20th century. Manometric flames were replaced by new instruments such as oscilloscopes.
A video demonstration of a Koenig harmonic analyzer recorded by David Pantalony is available on youtube here.
A video demonstration of a Koenig harmonic analyzer was also produced by the Fondazione Scienza e Tecnica in Florence, Italy and is on YouTube.
An article titled "The Manometric Flame" by Thomas B. Greenslade, Jr. on eRittenhouse on is available here.
When the air in a resonator vibrates, the vibration is transmitted through a rubber tube to a manometric capsule. The vibrating rubber membrane in the capsule modulates the flow of gas feeding a flame, causing it to vibrate, too.
The motions of the flames are too rapid to be perceived by the eye directly. However, by observing the flames in rotating mirrors, the flames appear as sawtoothed bands or strips of light. This is due to the persistence of the image on the viewer's retina. The flame of an excited resonator produces a saw-toothed image in the mirror. The flame of an unexcited resonator produces a luminous stripe without teeth.
By examination of the flames, one can determine the frequencies that combine to make up a compound sound. Koenig's harmonic analyzer, therefore, is like a Fourier analysis, in finding a combination of frequencies that compose a given sound.
This method of analyzing sound frequencies were widely used until the beginning of the 20th century. Manometric flames were replaced by new instruments such as oscilloscopes.
A video demonstration of a Koenig harmonic analyzer recorded by David Pantalony is available on youtube here.
A video demonstration of a Koenig harmonic analyzer was also produced by the Fondazione Scienza e Tecnica in Florence, Italy and is on YouTube.
An article titled "The Manometric Flame" by Thomas B. Greenslade, Jr. on eRittenhouse on is available here.
Primary SourcesFor references see: Koeing (1865) "Catalogue des Appareils D'Acoustique" pg. 46, no. 216. And Koenig (1889).