A Harmonium is a free-standing musical keyboard instrument similar to a Reed Organ or Pipe Organ. It consists of free reeds and sound is produced by air being blown through reeds resulting in a sound similar to that of an accordion. The air is supplied by foot-operated (or, as with the type of harmonium used in Indian music, hand-operated) bellows alternately depressed by the player.
Harmonium or Reed Organ?
The British introduced harmoniums to India during the colonial period.In North America, the most common pedal-pumped free reed keyboard instrument is known as the American Reed Organ, (or parlor organ, pump organ, cabinet organ, cottage organ, etc.) and along with the earlier melodeon, is operated by a suction bellows where air is sucked through the reeds to produce the sound. A reed organ with a pressure bellows, that pushes the air through the reeds, is referred to as a harmonium.In much of Europe, the term "harmonium" is used to describe all pedal pumped keyboard free reed i
Source:
http://en.wikipedia.org/wiki/Harmonium