The Æolian harp is a musical instrument which is set in action by the
wind. The instrument, which is not very well known, is yet very curious,
and at the request of some of our readers we shall herewith give a
description of it.
[Illustration: FIG. 1.--KIRCHER'S ÆOLIAN HARP.]
According to a generally credited opinion, it is to Father Kircher, who
devised so many ingenious machines in the seventeenth century, that we
owe the first systematically constructed model of an Æolian harp. We must
add, however, that the fact of the spontaneous resonance of certain
musical instruments when exposed to a current of air had struck the
observers of nature in times of remotest antiquity.
Without dwelling upon the history of the Æolian harp, we may say that in
modern times this instrument has been especially constructed in England,
Scotland, Germany, and Alsace. The Æolian harp of the Castle of Baden
Baden, and those of the four turrets of Strassburg Cathedral are
celebrated.
[Illustration: FIG. 2.--FROST & KASTNER'S IMPROVED ÆOLIAN HARP.]
We shall first describe Kircher's harp, which this Jesuit savant
constructed according to an observation made by Porta in 1558. The
instrument consists of a rectangular box (Fig. 1), the sounding board of
which, containing rose-shaped apertures, is provided with a certain
number of strings stretched over two bridges and fastened to pegs at the
extremities. This box carries a ring that serves for suspending it.
Kircher recommends that the box be made of very sonorous fir wood, like
that employed in the construction of stringed instruments. He would have
it 1.085 meters in length, 0.434 meter in width, and 0.217 meter in
height, and would provide it with fifteen catgut strings, tuned, not like
those of other instruments to the third, fourth, or fifth, but all in
unison or to the octave, in order, says he, that its sound shall be very
harmonious. The experiments of Kircher showed him the necessity of
employing a sort of concentrator in order to increase the force of the
wind, and to obtain all the advantage possible from the current of air
that was directed against the strings. The place where the instrument is
located should not, according to him, be exposed to the open air, but
must be a closed one. The air, nevertheless, must have free access to it
on both sides of the harp. The force of the wind may be concentrated upon
such a point in different ways; either, for example, by means of conical
channels, or spiral ones like those used for causing sounds to reach the
interior of a house from a more elevated place, or by means of a sort of
doors. These latter, two in number, are adapted to a kind of receptacle
made of boards and presenting the appearance of a small closet. In the
back part of this receptacle there is a slit, and in front of this the
harp is hung in a slightly oblique position. The whole posterior portion
of the apparatus must be situated in the apartment, while the doors must
remain outside the window (Fig. I). In later times the Æolian harp has
been improved by Messrs. Frost and Kastner, whose apparatus is
represented in Fig. 2. It consists of a rectangular box with two sounding
boards, each provided with eight catgut strings. In order to limit the
current of air and to bring it with more force against the strings, two
wings are adapted near the thin surfaces opposed to the wind, so that the
current may reach each group of cords on passing through the narrow
aperture between the obliquely inclined wing and the body of the
instrument. The dimensions of the resonant box are as follows: height,
1.28 meters; width, 0.27 meter; and thickness, 0.075 meter. Distance
between the two bridges, or length of the sonorous portion of the cords,
about 1 meter; width of the wings, 0.14 meter. Distance between the
sounding board and the wings, 0.42 meter. Inclination of the wings, 50
degrees.
[Illustration: FIG. 3.--ÆOLIAN HARP IN THE OLD CASTLE OF BADEN
BADEN.]
The celebrated Æolian harps of the old castle of Baden Baden are entirely
different, and merit description. One of them (Fig. 3) is formed of a
resonant box, the construction of which differs from that of Æolian harps
with a rectangular box, in that it is prolonged beyond the place occupied
by the strings, and is rounded off behind. In the opposite side there are
two long and narrow apertures. To prevent the apparatus from being
injured by the weather, it is inclosed in a sort of case occupying the
recess of the window in the old ruined castle in which it is exposed.
Behind the harp there is a wire lattice door, the purpose of which seems
to be to protect the instrument against the attempts of robbers or the
indiscreet contact of tourists. We annex to the general view of the
instrument a front and profile plan (Fig. 4). The Æolian harp has often
inspired both writers of prose and poetry. Chateaubriand, in _Les
Natchez_, compares its sounds to the magic concerts that the celestial
vaults resound. Without attributing such effects to the instrument, it
must be admitted that it possesses remarkable properties, which act upon
the nervous system and cause very different impressions, according to the
temperament of those who listen to its accords.
[Illustration: FIG. 4.--PLAN OF THE BADEN BADEN INSTRUMENT.]
Hector Berlioz, in his _Voyage Musicale en Italie_, has given as follows
the curious effects that an Æolian harp produced upon his lively and
impassioned imagination: "On one of those gloomy days that sadden the end
of the year, listen, while reading Ossian, to the fantastic harmony of an
Æolian harp swinging at the top of a tree deprived of verdure, and I defy
you not to experience a profound feeling of sadness and of _abandon_, and
a vague and infinite desire for another existence."
An English physician, Dr. J.M. Cox, in his practical _Observations_ upon
dementia, asserts that unfortunate lunatics have been seen whose
sensitiveness was such that ordinary means of cure had to be given up
with them, but who were instantly calmed by the sweet and varied accords
of an Æolian harp. Other observers narrate that they have heard the
efficacy of Aeolian sounds spoken of in Scotland for producing sleep.
Telegraph wires are often, under the influence of the winds, submitted to
vibrations which reproduce the phenomena of the Aeolian harp. The
electric telegraph, which, before the construction of the Kehl bridge,
directly traversed the Rhine, very frequently resounded, and the observer
who placed his ear against the poles on the bank of the river was enabled
to hear something like a far-off sound of bells.--_La Nature_.
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