"Yes; has it a meaning?"
"Certainly; it is our method of talking without direct communication."
"Have the kindness to give me the key to the vocabulary."
"It is not difficult; every letter has a rank in the alphabet."
"Decidedly."
"There are twenty-four letters."
"I have never counted them, but no doubt you are right."
"Well, one blow for a, two for b, three for c, and so on."
"I understand, but this method of communication must be somewhat lengthy, and I see a string at my window which is getting impatient—I will strike a blow or two to show my neighbor that I have heard him, and then attend to the string."
"Go, monsieur, I beg, for if I am not mistaken that string is of importance to me; but first strike three blows on the floor—in Bastille language that means patience; the prisoner will then wait for a new signal."