This we did; and I am bound to say, met with very great civility from the superintendent of the department in question. In spite of the admirable and systematic manner in which the huge establishment was carried on, it was not easy, and in many cases would have been impossible, to discover what individual had paid in any particular note; but every pains and trouble were taken in our behalf, to effect this. Out of the four notes, only one, No. 82979, could be identified as having been received from any particular person--one Mr. Worrall, a silk-merchant in the City. Having expressed our warmest thanks to the authorities, we immediately called a coach, and started off to this gentleman's warehouse. We were so fortunate as to find him in, although he was just upon the point of setting forth to his private residence. Upon an examination of his books, we discovered no record of the bank-note about which we were concerned; still, he frankly owned to us that such memoranda were not kept with excessive accuracy. "It is possible yet that the people at the Bank may have been correct," observed he. "You had better return there; and since the matter is one of life and death, I do not mind confiding to you, that if that note has passed through our hands at all, it will have the letter W, in red, upon the back of it; it is very small, but still can be deciphered without a magnifying-glass." "There was no mark," observed I, "upon any of the notes I saw." "There _was_ a mark," remarked the Bow Street runner, reflectively; and I am pretty sure it was upon this very note.--"It is no wonder that you did not see it, young gentleman, since your livelihood does not depend, as mine does, upon keeping my eyes about me. The mark in question was also almost obliterated by the red "Cancelled" which the Bank had placed upon the note; but as far as I could make it out, it was the letter O." "That is the private mark of the Metropolitan Oil Company," exclaimed Mr. Worrall, without hesitation. "Although, indeed, because I have told my own secrets, I am not sure that I am justified in revealing those of other people. Their offices are in the very next street to this."