17. 18 May 1968 (David Kahn; Elgar ciphers)
just a passing thought about the Elgar ciphers, perhaps of passing interest to you or Diana.
They're mentioned in a vast, fascinating and (I think) indiscreet compendium by David Kahn called The Codebreakers in a context (p. 800) suggesting that they're quite well known to the cryptanalytic hierarchy, and have proved intractable – like that awful Voynich manuscript which no one dare think about for fear of spending the rest of his life in an esoteric trance-state. Not a bad idea at that, come to think of if. Kahn also suggests (an obvious enough point) that the cryptogram may contain the enigma of the Enigma – because Elgar said to Dorabella that he thought she of all people would have guessed it.
These two points together – the cryptogram defeats language – cipher experts; the enigma, like the Enigma, is in essence musical – suggest perhaps that the Dorabella ciphers mean music. So the general system of 8 x 3 which seems to underlie them
i. e. 8 round a circumference, 3 on a radius in an unknown direction or order might suggest a scale of 8, d -d' x 3 (nat., b, #) a la Schumann or perhaps again, in Elgar’s case, plainchant with a mode of 8 x 3 (punctum, virga, diamond).For that, 87 notes so varied would seem to be about right. I expect Alec Robertson would recognise those symbols, even without (what's the word?) trans-notation, as the Easter Hymn or something, without hesitation.
It might be worth having a quick look at; as Kahn's book shows, born musicians are likely to be born cryptographers..