Harmonium a keyboard musical instrument, with the wind being supplied by bellows. Although it originated in the west, the harmonium has occupied a permanent place among Bengali musical instruments since the late nineteenth century. A Frenchman, Alexander Dorian, is credited with its invention in 1840. It is also known as 'Cabinet Organ'.
In appearance, the harmonium looks like a box. To play it, one needs to pump air inside it with the help of built-in bellows. Inside there is a reedboard, with metal reeds arranged according to the seventh diatonic scale of musical notes. The air that is pumped with the help of the bellows strikes the reeds, and musical notes emerge.
The keyboard comprises black and white keys. The white keys are for pure notes and the blacks ones are for soft ones. However, this is not applicable if the scale is changed.
During its initial stages, the harmonium was made in the diatonic scale for use in the west. However, there was no scope to change the keys, and thus it was quite difficult to modulate tunes. To solve this problem, the diatonic scale was changed into an equally tempered scale.
As the keys of the harmonium are arranged in a particular scale, one does not need to compose a tune to present a song. Thus, it is easily adapted to vocal practice.
It is probably for this reason that the harmonium has become so popular in Bangladesh. At present, the harmonium has become an indispensable and popular accompanying instrument for vocalists. Among the different kinds of harmoniums in use are Coppler Harmonium, Box Harmonium, Scale Change Harmonium, Single Bellows Harmonium, Double Bellows Harmonium, and English Bellows Harmonium.
It was probably in Kolkata that the harmonium was first used in Bengal. In the 1860s, dwijendranath tagore played it in his private theatre in Jorasanko. At the beginning people were curious, but gradually developed an interest in playing it. Several books were also written to help learners. Sourindramohan Thakur's Harmonium Sutra (1874) and krishnadhan banerjee's Harmonium Shiksa (1899) are the first, and most important, books that describe in detail how to play the harmonium. [Mobarak Hossain Khan]