A few days ago I posted a list of open questions about the dead cipher pigeon, really as a way of externalizing the annoyance I felt from knowing so few basic facts. To my great delight, Mike Moor from Melbourne and (well-known military history buff) Christos T. stepped forward with a whole wheelbarrowful of answers. And here they are…
“Did any British pigeon handlers ever use “lib.” as an abbreviation?”
Mike Moor points out that the first message sent back on D-Day was by Reuters reporter Montague Taylor, attached to the eg of the war-seasoned (and subsequently Dickin-Medal-receiving!) carrier pigeon Gustav [NPS.42.31066]. At the bottom of the image (clearly on an RAF pigeon message pad), it says “Liberated 0830” (click to see the full message):-
“Why can’t I find a single other message written on the same printed pigeon service pad?”
For this, Mike Moor points to a message sent by Major General Roberts on a page talking about the Canadian armed forces’ involvement in World War Two. [Incidentally, the abortive Canadian raid on Dieppe was known as "Operation Rutter", I wonder if Stu R knew that?] Even though the quality of the scan is frankly diabolical, it’s very much better than nothing at all, and tells us that this our pigeon message was (without any real doubt) an Army Pigeon Service message pad.
Mike also notes that this was an “Army Book 418B”, the updated version of the Army Book 418 used for pigeon messages in the First World War. It turns out that the National Army Museum near Sloane Square tube in London has an Army Book 418B in its collection described as “Army Book 418B, Pigeon Service Message Book, 1942″, accession number “1975-06-35″: it would be cool to ask the curators there to have a closer look.
“Was the pigeon message we have a hectograph or a carbon copy?”
Mike Moor notes “It is a carbon copy pad with 1 original retained in the book and 2 carbon copies made – which lines up with what you’d expect from the message i.e. 2 copies sent and the blue text of the cipher looks a lot like a carbon copy + black amendments by a second hand presumably prior to sending.” Excellent, thanks!
“When did Slidex change from having one letter per horizontal key slot to two letters per slot?”
The (plainly utterly indefatigable) Mike Moor points us to some December 1944 Slidex instructions available on Rob van Meel’s site (a copy will cost you two euros plus international postage from the Netherlands), by which time it had changed to two letters per key slot on the horizontal cursor. That narrows the range down dramatically to ‘sometime in 1944′… we’ll just have to keep digging to find out exactly when in 1944. At least this is a question that we can reasonably hope to get a solid answer on!
“When were Slidex Series B code cards introduced?”
In the Series A “RE No. 2″ (Army Code No. 14070) Card 35 that I got from the excellent royalsignals.org.uk website, the three columns have had their shape changed to break up the columnar structure somewhat, which I believe may point to a rethink & upgrade of the Slidex code during WW2.
At the same time, another Series A card has two versions, one with an Army code and another with a different W.O. (War Office) code, which I suspect points to a post-WW2 handover from the Army to the War Office. But that’s as good an answer as this question has for now.
“Did Bletchley Park / GCHQ ever catalogue the tons of files brought back by the TICOM teams?”
Christos replies: “There are many TICOM file categories: I, IF, DF, M, D. Captured German documents had to be catalogued and then translated. This must have taken years. The question is whether there is a full list of those files. There is a DF list but I don’t know about any document covering the other files.”
Incidentally, p.38 of TICOM I-109 (a report by Lt Ludwig of Chi Stelle OB.d.L) says:
B. Slidex system.
Bigram substitution system.
In use in the army (front line units) and in air support networks (tentacle networks).
The system was known from the monitoring of exercises in Great Britain before the invastion, e.g. “Spartan”. The cryptanalytic detachments in army and GAF were able to get so much experience on these exercises that decoding worked well right at the start of the invasion.
Recovery was done in the army again at NAA St 5, in the GAF in 14/3 (W control 3).
Decoding was often done with so little delay that the messages could be dealt with like clear text in the evaluation.
The results were of more importance to the army than to the GAF, but theu provided the latter too with valuable indications, e.g. elucisation of the individual corps tentacle networks, reconnaissance operations (e.g. 400 and 414 Squadrons) etc.
The messages decoded daily were exchanged between Army and GAF in the form of written reports.