Aeolian Harp, or harp of AEolus, is a musical instrument, which probably received its name from the effects produced upon it by the air without human aid. It consists of a slight box of fibrous wood, usually deal, containing a low bridge at each end, over which is stretched, upon pegs, a series of fine cat-gut strings, generally about fifteen in number, which, being of equal size and length, are therefore unisons. Its length should correspond with the size of the window or other aperture where it may be placed; its width need not be more than from 4 to 6 inches, and in depth from 3 to 4 inches. It should be placed between the lower sash and sill of a window, with its strings uppermost, under which is a circular opening, as in the belly of the guitar. When the wind blows athwart the strings, it produces the effect of a choir of music in the air, swelling or diminishing its sounds according to the strength or weakness of the blast.