| This small siren, in the collection of St. Mary's College
in Notre Dame, Indiana, is listed in the 1889 Koenig catalogue as "Cagniard
de Latour's Siren, with counter ... 90 francs"; this was about $18.00 in
contemporary U.S. funds.
This siren is illustrated in the catalogue placed in "Cavaillé-Coll's small air regulator". This was a small wind chest with bellows mounted on top of it, and a weight to maintain a constant air supply from the bellows to the siren. Cavaillé-Coll was a well-known Parisian builder of church organs at the end of the nineteenth century.
The origin of the siren is discussed in the chapter on acoustics. The device gives an absolute measurement of the frequency of a sound: air pressure causes the disk at the bottom to spin, cutting off puffs of air that create the sound. The number of turns of the disk in a given time can be read off the dials at the top of the apparatus. The left-hand dial registers revolutions in hundreds. Unfortunately, the indicating needles have been lost from this apparatus.
|This fine example of Helmholtz' double siren can be found in the collection of the National Museum of American History at the Smithsonian Institution in Washington, D. C. My notes indicate that this siren is by Koenig, although the 1889 Koenig catalogue shows the model with a cast iron base that is described elsewhere.|
| This double siren, at Wesleyan University in Middletown,
Connecticut, was clearly made by Koenig, although it is not described in
his 1889 catalogue.
On the other hand, it is illustrated in the book, Sound and Music by J. A. Zahm of Notre Dame University, published in 1900. Zahm regularly visited Koenig and used illustrations supplied by him. The apparatus is illustrated in the 1889 catalogue of James W. Queen of Philadelphia, and is listed at $100.00.
An identical piece of apparatus
is in the collection of Glasgow University in Scotland.