I wish to add a little teaser: Reading the 1844 patent text carefully reveals several confusing miswritings or misunderstandings that makes me wonder if the text is intentionally contradictory in order to confuse possible readers or if CW did not quite understand what he was up to himself??
Anyhow I really doubt if he ever touched - or even more - ever tried to play - his instruments, and if they for his own part firslty were theoretical creations that by accident came out as objects in reality.

Am I talking nonsense? If you are curious do check "improvement" No:s 2, 5 and 7 in the 1844 patent papers...

Well - there is a possible rational explanation... the patent application may have been just a framework but that is contradictory too since it does contain the very sensible Improvement 1,first arrangement which is the "Double" concertina keyboard layout - a very useful 'duet' system idea which sadly enough was not successful.