An Edinburgh Organ Treasure

Wednesday August 7

Dr John Kitchen, Edinburgh City Organist, reflects on the hidden history of an organ in central Edinburgh.

THE world-renowned Collection of Early Keyboard Instruments in St Cecilia’s Hall in the University of Edinburgh contains an unusual ‘enharmonic’ chamber organ. 

It dates from about 1760, has a single keyboard and no pedals, and was built by Thomas Parker. In 1768 he built another enharmonic organ for the Foundling Hospital in London, an institution with which Handel had a close association—although Handel died in 1759 and so could not have played Parker’s organ.

What is an ‘enharmonic organ’ and what is its purpose?  Well, the instrument has separate pipes for the enharmonic equivalents such as G sharp/A flat, D sharp/E flat and so on.  When we learn the piano, we are told that G sharp and A flat are the same note, as indeed they are on the piano, as well as on most organs and other keyboard instruments.   But scientifically they are not the same note; they are quite significantly different in pitch!  Next time you are speaking to a violinist, ask them if they play G sharp and A flat on the same place in the string!   String players, singers, and (to a lesser extent) wind players can make subtle differences in these pitches, something which keyboard players cannot do on normal keyboards. 

What we are used to is a compromise; on the piano we hear a pitch which is between the two.   This system is called ‘equal temperament’ in which all the semitones between each octave are same distance apart.  But we are used to this compromise which became necessary in the 19th century, when composers increasingly wanted to use the complete range of keys and write music in keys like G flat!   Prior to the 19th century, various ‘unequal’ temperaments were used, in which the most-used keys were very well in tune, but more remote keys less so, or even unusable. 

This still applied in the time of Bach, Handel, Mozart and Beethoven (all of whom generally avoided the more extreme keys) and into the early 19th century.    Interestingly, musicians knew about equal temperament from at least the beginning of the 17th century and could have applied it to their keyboard instruments.    But they seem not to have liked it for the reason I mentioned above:  everything is ‘sort of’ in tune, but nothing is precisely in tune!

The Parker organ is equipped with two levers which operate extra pipes for the enharmonic equivalents, and when playing, these levers have to be adjusted to change from, say, G sharp to A flat, depending on the requirements of the music being played.   But why go to all this trouble?   Well, these arrangements allow for ‘pure thirds’ to be played which scientifically are perfectly in tune—and they sound wonderful!    You don’t get any absolutely pure thirds on a modern piano or organ. These thirds give the music an extra vitality and excitement and can sound really thrilling; they are particularly effective on an organ because of its sustained tone.

Our organ at St Cecilia’s would have been used in secular chamber music, in accompanying instruments and voices—as well as in solo repertoire.    This is a reminder, too, that organs have always had an important place in secular music-making, in concert halls and indeed in the private houses of those who can afford them; organs should not be associated exclusively with the church.  St Cecilia’s Concert Hall and Museum is in Cowgate, Edinburgh, and is open free to the public five days a week, when this organ—and many other treasures—can be seen.  

Dr John Kitchen is Edinburgh City Organist, music scholar and educator.

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