Natural Magic.
THE ÆOLIAN HARP consists of an oblong box of thin deal board about five or six inches deep, with a circle drawn in the middle of the upper side, an inch and a half in diameter, around which are to be drilled small holes. Along the upper side of the box seven, ten or more small strings of very fine gut are stretched over bridges near each end, like the bridges of a violin, and tightened or relaxed with screw pins. The strings must be tuned to one and the same note, and the instrument placed in some current of air where the wind can pass over its strings with freedom. A window, the width of which is exactly equal to the length of the harp, with the sash just raised to give the air admission, is a good situation. When the wind blows upon the strings, with various degrees of force, different musical tones will be sounded; sometimes the blast brings out all the tones in full concert, and sometimes it sinks them to the softest murmur. In many old castles these harps were fastened in the windows, and their wild music caused the ignorant to think they were haunted.
A colossal imitation of the instrument just described was invented at Milan, in 1786, by Abbate Gattoni. He stretched seven strong iron wires, tuned to the notes of the gamut, from the top of a tower sixty feet high, to the house of a Signor Muscate, who was interested in the success of the experiment; and this apparatus, called the giant’s harp, in blowing weather yielded lengthened peals of harmonious music. In a storm this music was sometimes heard at the distance of several miles.
Simply tying waxed saddler’s silk to little sticks, and pushing them into the crevices of windows, so as to receive a draft of wind (the silk being strained tight), will produce very sweet sounds.