The Stratagem and Other Stories

three, while in one corner is a much larger and thicker cross and two smaller crosses not so symmetrical. This group represents the element of chance; and you will at least gain a hint of the truth if you reflect that eight is the cube of two, and twenty-seven of three.” Bevan looked intelligent. “On the return march,” continued Duguesclin, “Dodu said, ‘The spy is on the watch. But count the letters in the name of Aristotle’s favourite disciple.’ I guessed (as he intended me to do) that he did not mean Aris- totle. He wished to suggest Plato, and so Socrates; hence I counted A-L-C-I-B-I-A-D-E-S = 10, and thus completely baffled the spy for that day. The following day he rapped out ‘Rahu’ very emphatically, meaning that the next lunar eclipse would be the proper moment for our evasion, and spent the rest of the day in small talk, so as to lull the suspicions of the spy. For three days he had no opportunity of saying anything, being in the hospital with fever. On the fourth day: ‘I have dis- covered that spy is a damned swine of an opium- smoking lieutenant from Toulon. We have him; he doesn’t know Paris. Now then—draw a line from the Gare de l’Est to the Etoile; erect an equilateral triangle on that line. Think of the name of the world-famous man who lives at the apex.’ (This was a touch of super- genius, as it forced me to use the English alphabet for the basis of the cipher, and the spy spoke no language but his own, except a little Swiss.) ‘From this time I shall communicate in a cipher of the direct additive nu- merical order, and the key shall be his name.’ “It was only my incomparably strong constitution which enabled me to add the task of deciphering his conversation to that imposed by Government. To memorise perfectly a cipher communication of half-an- hour is no mean feat of mnemonics, especially when the deciphered message is itself couched in the obscurest symbolism. The spy must have thought his reason in danger if he succeeded in reading the hieroglyphs which