The five organ pipes below at the United States Military Academy at West Point are by Marloye. More interesting are the Marloye pipes still being used for lecture demonstrations at Harvard University.
| Koenig made a great array of scientific organ pipes, mostly
diapason-types made of wood. Their survival rate is pretty good, judging
from the numbers I have seen in American collections. Occasionally I see
pipes made by his predecessor, Albert Marloye (1785-1874), whose mark can
be seen on a Union College pipe at the right.
The five organ pipes below at the United States Military Academy at West Point are by Marloye. More interesting are the Marloye pipes still being used for lecture demonstrations at Harvard University. |
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This organ pipe, at West Point, is part of catalogue number
114 in the 1889 Koenig catalogue, "Eight stopped pipes giving the scale
from Ut(3) to Ut(4) ...60 francs"
When the end plug is removed the pipe becomes an open pipe, and the frequency approximately doubles. |
| Item number 97 in the 1889 Koenig catalogue is "Nine pipes, five of the same depth but of different lengths, giving [a range of frequencies] and four of the same length but of different depths, giving [another range of frequencies]. The deepest pipe of the group of four in the cut rather resembles this oddly-proportioned pipe at Union College. |  |
  
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Then there are pipes to allow the experimenter to investigate
the node in the middle of an open organ pipe.
The top pipe is at the University of Toronto, and is catalogue number 89 in the 1889 Koenig catalogue, listed as "Pipe to give the second harmonic, with opening at a loop ... 8 francs" With the opening covered with the toggle, is possible to have a node at the center of the pipe, which sounds the fundamental. Placing a hole at the center pipe forces an antinode at that point, and the second harmonic is sounded. The second and third pipes are at Wesleyan University and
the University of Toronto, and are catalogue number 88: "Pipe that can
be closed at a node ... 10 francs" Since there is no movement of air in
a [displacement] node, it does not matter if the solid portion of the slider
or a portion with a hole in it is at the middle of the pipe sounding the
fundamental frequency.
The fourth organ pipe, also at Toronto, is catalogue number 90: "Pipe
with different openings at node ... 20 francs." The accompanying text in
the 1889 Koenig catalogue notes that the sound increases with the diameter
of the hole.
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| This long, thin pipe at the University of Toronto can immediately be assumed to give a number of higher harmonics with only moderate overblowing. It is listed as item number 104 in the 1889 Koenig catalogue: "A long open pipe, giving the sounds 1, 2, 3, 4... 21 francs" |  |
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Here is another variation on the theme of pipes giving
various overtones.
This pipe, at the University of Toronto, has a mouthpiece at the middle, and pistons at both ends. These are fixed, and the pipe can be slid up and down. It resembles closely item number 106 in the 1889 Koenig catalogue, and is listed as "A long pipe, stopped at both ends, giving the sounds 1, 3, 5, when the mouthpiece is fixed, and the sounds 1, 2, 3, 4, when movable. 52 francs" There are also small holes in the lower half of the pipe that may be open or closed with flaps.
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| This organ pipe, at the University of Toronto, is a mystery. Zahm makes no reference to it and it is not in Koenig's 1889 catalogue. It must have been used to show the transition from closed to open pipe as the slider was moved sideways. |  |
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This is two thirds of a set of three organ pipes with resonators
made of different materials;
the third tube is made of brass. The set, at the University of Toronto,
is catalogue number 96 in the 1889 Koenig catalogue, where it is listed
at 30 francs.
The catalogue text notes that all three resonators give essentially the same sound. |