“I had turned my back, having given some excuse for my presence to one of the clerks, who is an acquaintance. Thus the lady, who knows me, could not see my face; but I could, by looking out of the corners of my eyes, see _her_. She came in, in her rich gray cloak, smiling on the clerks, and handing an open letter to one of them, said:--“‘Will you oblige me by sending that to my sister in New York, by the flag-of-truce boat, to-morrow, sir?’ “‘If there is nothing contraband in it, madam,’ said the clerk. “‘Oh!’ she replied, with a laugh, ‘it is only on family matters. My sister is a Southerner, and so am I, sir. You can read the letter; it is not very dangerous!’ “And she smiled so sweetly that the clerk was almost ashamed to read the letter. He, however, glanced his eye over it, and evidently found nothing wrong in it. While he was doing so, the lady walked toward the mail-bags in which the clerks had been placing such letters as they found unobjectionable, the others being marked, ‘Condemned,’ and thrown into a basket. As she passed near one of the bags, I saw the lady, whom I was closely watching, flirt her cloak, as though by accident, across the mouth of one of the mail-bags, and at the same instant her hand stole down and dropped a letter into the bag. As she did so, the clerk, who had finished reading _the other letter_, bowed, and said:--- “‘There is nothing objectionable in this, madam, and it will be sent, of course.’ “‘I was sure of that, sir,’ replied the lady, with a smile. ‘I am very much obliged. Good evening, sir!’ “And she sailed out, all the clerks politely rising as she did so. “No sooner had the door closed than I darted upon the bag in which I had seen her drop the letter. The clerks wished to stop me, but I informed them of what I had seen. If they doubted, they could see for themselves that the letter, which I had easily found, was not sealed with the seal of the bureau. They looked at it, and at once acknowledged their error. “‘Arrest her!’ exclaimed one of them, suddenly. The rapid rolling of a carriage came like an echo to his words. “‘It is useless, gentlemen,’ I said. ‘I know where to find the lady, and will look to the whole affair. You know I am in the secret service, and will be personally responsible for every thing. I will take this letter to the official who directed me to watch the lady who brought it.’ “To this, no objection was made, as I am known at the office. I came away; returned as quickly as possible; and here is the letter, sir.” With which words Nighthawk drew his hand from under his cloak, and presented the letter to Mr. X-----, who had listened in silence to his narrative. VIII. BY FLAG-OF-TRUCE BOAT. MR. X----- took the letter, broke the seal, and ran his eye over the contents. “Decidedly, that woman is a skilful person,” he said; “she fishes in troubled waters with the coolness of an experienced hand.” And presenting the letter to me, the statesman said:--