Some months ago, I wrote about a British book cipher during the American Revolutionary War. This time, I uploaded a new article about Wellington's dictionary code: "Wellington's Polyalphabetic Cipher with a Dictionary Code". For words/names not found in the dictionary, a polyalphabetic cipher with heavy nulls was used.
My observations are based on Wellington's despatch to General Maitland dated 2 September 1812. I thank George Lasry for the information of the auction of the letter at Spink.
I added a fuller acknowledgement of the auction website in the preamble of my article. Before me, the website already included an analysis of the letter by an expert who works with the auction house, who expresses "special thanks to cryptanalyst George Lasry for providing his expertise". The reader will see that they had already established the full scheme of the dictionary code, associated it with Scovell based on what Urban writes about a similar scheme, identified what I call "Key 1" for the substitution cipher, and also quoted relevant letters.
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