(Ger. Handharmonika, also Ziehharmonika). A portable instrument of the free-reed species, invented at Vienna by Damian, in the year 1829. It consists of a small pair of hand-bellows, to one side of which is affixed a key-board, containing, according to the size of the instrument, from five to fifty keys. These keys open valves admitting the wind to metal reeds, the latter being so arranged that each key sounds two notes, the one in expanding, the other in compressing the bellows. The right hand is placed over the key-board, while the left works the bellows, on the lower side of which are usually to be found two keys which admit wind to other reeds furnishing a simple harmony—mostly the chords of the tonic and dominant. It will be seen that the capabilities of the instrument are extremely limited, as it can only be played in one key, and even in that one imperfectly; it is, in fact, but little more than a toy. It was originally an extension of the ‘mouth-harmonica’ — a toy constructed on a similar principle, in which the reeds were set in vibration by blowing through holes with the mouth, instead of by a key-board. This latter instrument is also known as the Æolina.