He was seized again with coughing; Jack waited anxiously for the paroxysm to cease.

"I regret to tell you the letter is gone."

"Gone!" echoed Jack blankly.

"Gone, Señor."

"But how—why—can it have been lost, mislaid?"

"It was locked in my cabinet. A fortnight ago my cabinet was rifled, and a box of papers was taken away, among them the letter addressed to your father."

"But still I do not understand, Señor. Why should anyone wish to steal a letter addressed to an unknown Englishman?"

"No one wished that, I suspect," said Palafox with a faint smile. "The box in which the letter was placed was exactly similar to another box containing papers of public importance, including plans for the defence of the city. That, as I surmise, was the box which the thief wished to secure. Luckily for Spain, unluckily for you, he stole the wrong box, and apart from your letter obtained nothing of any great importance."

"I am glad of that," said Jack instantly. "Of course I am disappointed and vexed about the letter, but a private loss like that does not matter half so much as the loss of your plans would have done; it's no good crying over spilt milk, as we say, and I must put up with it."

"It is good of you to take the matter with such noble resignation," said the courtly Spaniard. "Believe me, I regret the circumstance exceedingly. I can only hope that the French spy who stole the box—he must have been a French spy; we have no afrancesados in Saragossa—I can only hope that there was nothing in the letter that will seriously affect your fortunes, and after all, it was a duplicate, and the original is probably safe with your father in London. And now tell me, Señor, how you succeeded in the daring and marvellous feat of entering our sorely invested city."