Tuning Forks
     In addition to tuning forks on resonators and electrically-driven tuning forks, Koenig made many other tuning forks. For example, at the right is a large fork used to help students experience low frequencies. The weights on the tines can be moved up to decrease the frequency, and down to decrease it. This is item number 48 in the 1889 Koenig catalogue, and is at the University of Toronto. 

   Koenig also made a set of eight forks to determine the upper limit of hearing by producing beats between the forks.

   The tuning fork at the left stands about 60 inches high. It is clearly the "large fork from 32 to 48 s.v. [16 to 24 Hz] to determine the lowest limit of sound ... 300 francs" (about $60) that is listed in the 1889 Koenig catalogue.

   At present it is in the storage room at Cornell University, but ought to be put back into regular service in demonstration lectures to introductory students.

   Conversely, this appears to be a set of ten forks to determine the upper limit of human audition. The entire set was 18 forks, and cost 900 francs, including the iron stand.
   This somewhat rusty set of 25 forks at the United States Military Academy at West Point, New York form a tonometer, with, as I recall, frequencies differing from each other by 4 Hz. This is certainly part of the collection bought by the U. S. Government from Koenig after the 1876 Centennial Exposition in Philadelphia.
   The hand-held tuning fork at the left is at Dartmouth College. 

   At the right is a tuning fork designed to be clamped into a frame, perhaps next to another with a nearby frequency to demonstrate audible beats. These tuning forks have a good deal of mass, and will ring for a relatively long time,

   This Koenig hand-held tuning fork was in a lecture preparation room at the University of Texas at Austin when I visited in January 2003. In this form, it is useful for illustrating the directionality of the sound from a tuning fork by placing it vertically and then rotating it. In another demonstration, one of the tines can be covered with a cardboard tube and the consequences noted.

   The Koenig tuning forks below are at the University of Toronto. They appear to be hand-held, and are not listed in the 1889 Koenig catalogue.

   This set of five forks may have been used to demonstrate beats. A special stand was used to clamp two forks side by side so that they could be struck one after another. The set is at the United States Military Academy at West Point, New York.


The set of four tuning forks below have mirrors on their ends, and were designed to demosntrate Lissajous Figures. They are at Case Western Reserve University in Cleveland, Ohio.

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