The accordion is one of several European inventions of the early 19th century that use free reeds driven by a bellows. An instrument called "accordion" was first patented in 1829 by Cyrill Demian, of Armenian origin, in Vienna. Demian's instrument bore little resemblance to modern instruments. It only had a left hand buttonboard, with the right hand simply operating the bellows. One key feature for which Demian sought the patent was the sounding of an entire chord by depressing one key. His instrument also could sound two different chords with the same key, one for each bellows direction (a "bisonoric" action). At that time in Vienna, mouth harmonicas with "Kanzellen" (chambers) had already been available for many years, along with bigger instruments driven by hand bellows. The diatonic key arrangement was also already in use on mouth-blown instruments. Demian's patent thus covered an accompanying instrument: an accordion played with the left hand, opposite to the way that contemporary chromatic hand harmonicas were played, small and light enough for travelers to take with them and used to accompany singing. The patent also described instruments with both bass and sections, although Demian preferred the bass-only instrument owing to its cost and weight advantages.