The aeolodion or aeolodicon (also called in Germany Windharmonika) is an obsolete keyed wind instrument resembling the harmonium, its tone being produced from steel springs. It had a range of six octaves, and its tone was similar to that of the harmonium. After its invention around 1800, several modifications were made, including the aeolsklavier, aeolomelodicon or choraleon, and aeolopantalon, but all versions had largely disappeared by mid-century.