You may remember me talking about getting some bits together to research concertina pneumatic issues. Well, the slow boat from China has come in, and the even slower boat that is me seems to have got its act together. Here's the result:
An explanation of what it it comprises is at http://www.mcgee-flutes.com/Concertina/Concertina%20pneumatics%20lab.htm
An interesting little challenge that came up too.