A melodica is a free-reed instrument that is played by blowing air through a mouthpiece in the side of the instrument. A keyboard on top allows notes to be played by opening a hole for air to flow over a reed and create a note. Most melodicas have keyboards that are 2 or 3 octaves long.
The modern melodica was invented in the 1950's by the music company Hohner.
Other forms have been around since the 19th century.
One of the most important melodica players ever, Augustus Pablo was the first to use the melodica in reggae and was also instrumental in popularizing the genre of Jamaican dub. Pablo was most active during the 1970's as a both a recording artist and record producer.
Born Horace Swaby in St. Andrew, Jamaica in 1954 Pablo attended the Kingston College School where he learned to play the organ. It was during this time that a young girl lent him a melodica, which was used at the school to help teach kids learn music. Pablo quickly became obsessed with the instrument, playing it all the time. As his proficiency on the melodica grew, Pablo became more and more interested in using it in reggae.