Last week, after a student asked me what was bigger than an augmented interval, and I had no answer, this Associated Board Forum provided very helpful responses.

Today I shared some of the information with the student who had asked me. He was impressed by a "double augmented interval", and his mother told me he had told her he'd figured it was that. He was more impressed by one answer in the Forum which described 16th and 17th centuries organs having 53 notes per octave. Neither of us had any idea how an octave could have 53 notes. When my student left me, he wondered as he walked home. There he did some pretty amazing research which he has just shared with me by email. He'd found significant information about the organ, its creator, and its mathematical computations. I thought I'd pass on the information.

If you would like to see what the 53-notes-per-octave reed organ looks like, go to the following website:
www.wendycarlos.com/photos2.html The organ isn't easy to find. Go to "Fuzzy Critters" and after many photos of cats, you will come to the section "Photo Miscellany" where the first entry is "An Historic Microtonal Instrument from England". That's the organ with 53 notes in an octave.

There is more information at: http://en.wikipedia.org/Robert_Holford_Macdowall_Bosanquet

The mathematical computations are far beyond me, but maybe my student can understand it. He wants to be an architect so he's very good in Maths.

Thanks for that!

That's amazing...

The article just below is good too

I can see how my post suggested Renaissance organs with a 53-note octave, but as far as I know the most that they ever made had 19, and that was a one-off. As few as 13 could be useful (split Ab/G#) and the usual maximum, with all the black keys split, was 17. While they split-key organs were not common, I don't think of them as experimental: they met a real reqirement in a practical way and some of them still exist (I believe in working order). The keyboards with 13 to 17 keys look very like standard 12-note ones, while the Bosanquet inspired design is substantially different. When I saw the Bosanquet harmonium in the Science Museum in about 1950 I think I knew (it may have been so captioned) that it was a 19th C. invention. I'm sorry I didn't make that clear.

thanks for this interesting post