The idea for the free reed was derived from the Chinese sheng through Russia after 1750, and the first Western free-reed instrument was made in 1780 in Denmark.

The finer pump organs had a wider range of tones, and the cabinets of those intended for churches and affluent homes were often excellent pieces of furniture.

The Indian harmonium is widely used by Sikhs, Hindus and Muslims for devotional genres like qawwali, ghazal, kirtan and bhajan.

[2] Christian Gottlieb Kratzenstein (1723–1795), professor of physiology at Copenhagen, was credited with the first free-reed instrument made in the Western world, after winning the annual prize in 1780 from the Imperial Academy of St.

Hector Berlioz included it in his Grand traité d'instrumentation et d'orchestration modernes, published in Paris by Schoenberger, [1843?]

Beginning in 1885, the firm of Mason & Hamlin, of Boston made their instruments with the suction bellows, and this method of construction soon superseded all others in America.

They were especially popular in small churches and chapels where a pipe organ would be too large or expensive; in the funeral-in-absentia scene from Mark Twain's The Adventures of Tom Sawyer, the protagonist narrates that the church procured a "melodeum" (a conflation, likely intended by Twain for satirical effect[citation needed], of the names "melodeon" and "harmonium") for the occasion.

An added attraction of the harmonium in tropical regions was that the instrument held its tune regardless of heat and humidity, unlike the piano.

This "export" market was sufficiently lucrative for manufacturers to produce harmoniums with cases impregnated with chemicals to prevent woodworm and other damaging organisms found in the tropics.

For missionaries, chaplains in the armed forces, travelling evangelist etc., reed organs that folded up into a container the size of a very large suitcase or small trunk were made; these had a short keyboard and few stops, but they were more than adequate for keeping hymn singers more or less on pitch.

By this time, harmoniums had reached high levels of mechanical complexity, not only through the demand for instruments with a greater tonal range, but also due to patent laws (especially in North America).

And as its vibrators also admit of a delicate and durable tuning, it appeared to me peculiarly suitable for experiments on a more perfect system of tones.

[11] Additional modified or novel instruments were used for experimental and educational purposes; notably, Bosanquet's Generalized keyboard was constructed in 1873 for use with a 53-tone scale.

[12] Lord Rayleigh also used the harmonium to devise a method for indirectly measuring frequency accurately, using approximated known equal temperament intervals and their overtone beats.

[13] The harmonium had the advantage of providing clear overtones that enabled the reliable counting of beats by two listeners, one per note.

However, Rayleigh acknowledged that maintaining constant pressure in the bellows is difficult and fluctuation of the pitch often occurs as a result.

[19] Radiation patterns and coupling effects between the sound box and the reeds on the timbre appear not to have been studied to date.

[15] This particular aerodynamics is nonlinear in that the maximum displacement amplitude in which the reed can vibrate is limited by fluctuations in damping forces, so that the resultant sound pressure is rather constant.

[citation needed] Harmoniums played a significant part in the new rise of Nordic folk music, especially in Finland.

John Lennon played a Mannborg harmonium[26] on the Beatles' hit single "We Can Work It Out", released in December 1965, and the band used the instrument on other songs recorded during the sessions for their Rubber Soul album.

German singer Nico was closely associated with the harmonium, using it as her main instrument, during the late 60s and 70s, on albums such as The Marble Index, Desertshore and The End....[31] Donovan employed the harmonium on his 1968 album The Hurdy Gurdy Man where he played it in droning accompaniment on the song "Peregrine", and where it was also played on his song "Poor Cow" by John Cameron.

[32] Robert Fripp of King Crimson played a pedal harmonium borrowed from lyricist Peter Sinfield on the title track of the progressive rock band's 1971 album Islands.

What Crisis?, "Fool's Overture" from Even in the Quietest Moments..., the title track to their 1979 album Breakfast in America and "Lord Is It Mine".

Its lightweight design, portability, and ease of learning contributed to its widespread adoption among Sikhs, Hindus, and Muslims for devotional purposes.

Notably, it also found popularity in the Western yoga subculture, thanks to figures like Krishna Das and Jai Uttal.

In the 20th century, the harmonium faced controversy in Indian classical music due to technical limitations such as the inability to produce slurs, gamaka, and meend.

[39] Despite this, it became the instrument of choice for North Indian classical vocal genres, supported by its ease of learning and suitability for group singing.

The harmonium is popular to the present day, an important instrument in many genres of Indian, Pakistani, and Bangladeshi music.

[40] In the view points of preservation of cultural properties, maintenance and restoration, the pump organs are often categorized into several types.