more common to find switches on a chromatic or piano accordion. Variations Button accordions are found with a wide variety of keyboard systems, tuning, action, and construction. The diatonic button accordion is bisonoric, meaning when a button is pressed, the note sounded changes depending on whether the bellows are being expanded or contracted. This is similar to the harmonica, where the note changes depending on whether the player is breathing in or out. In most diatonic button accordions, each row of melody buttons produces a different major scale, with accidentals on 'helper buttons' at the ends of the rows. The diatonic button accordion is the most popular type of button accordion, and appears in many cultures, especially in folk music. One popular type of diatonic button accordion is the standard, one-row button accordion. This is tuned to a diatonic, 2.5 octave scale. The accompaniment side (bass/chordal side) buttons play a tonic chord when pushed, and dominant chord when pulled. This works well and is popular in basic Anglo-American fiddle tunes. The German melodeon was a popular, later version of a diatonic button accordion, especially in Scotland until around the 1920s. The chromatic button accordion is very similar to piano accordion, but can have 3, 4, or 5 rows of buttons on the right hand side. It is unisonoric, meaning the same note is sounded whether the bellows are pushed or pulled. The chromatic button accordion is traditionally used in a concert setting, and is more popular in jazz and classical music because it can be freely played in any key, usually with identical fingering patterns. History The first diatonic button accordion was patented under the name 'Accordion' in 1829 by Cyril Demian. The same year, Charles Wheatstone made the first concertina. The first chromatic button accordion was made by Franz Walther in 1850. The name 'Accordion' is thought to originate from , the German word for the major triad that is played when the bass buttons are sounded. The accordion may have originated with traditional reed instruments from southeast Asia. The button accordion was first mass-produced in Europe in 1835, with the piano accordion coming later. It was the first mass-produced, loud, durable, portable instrument – though it was not cheap. At first, the button accordion was too expensive to be very common among the lower and middle classes, but as it lost its novelty (around the 1860s), it became