Bass helicon in Bb (detail), C.G. Conn Ltd., Elkhart, Indiana, ca. 1888/89 (Musikinstrumentenmuseum Schloss Kremsegg, Austria, Streitwieser collection)
The sound of the earth, deep underground, when layers slowly shift and cover each other. Sounds that echo in subterranean caves. This sound cannot detach itself from the earth, it remains earth-bound, is heavy. The sound is inescapable, it is as inexorable as a natural disaster once let loose; when it rests it lies heavy over the earth.