I have not described the den near the Barbican with any great particularity, but I have said that the office, accessible from the open street, was only connected with the hidden premises behind--premises, as was afterwards discovered, held under a separate tenancy--by an easily-shifted ladder. It was in these hidden premises, approached by the maze of courts and the stable-yard, that the main evidences of Mayes's way of life were observable. The passage where my wrist had been locked to the wall, and the room or cellar in which Plummer had been confined, were the only parts of the lower premises fitted for the detention of prisoners, with the exception of one very low and wholly unlighted cellar, entered by a trapdoor and a very steep flight of brick steps. This place smelt horribly faint and stagnant; but it produced on my mind, both then and when I examined it later, an effect of horror and repulsion more than could be accounted for by the smell alone. Of its history nothing was discovered, and perhaps the feeling (though others experienced it as well as myself) was the effect of mere fancy; but I have never got rid of a conviction that that black cellar, or rather pit--for it was very narrow--had been the instrument of crimes never to be told. There were one or two rooms sparely furnished--one as a bedroom, a larger room, with a long table, a sofa, and several chairs; and in one of the smaller rooms was found a stove, ladles and crucibles for the melting down of metals--gold or silver. It was in this same room also that the table stood, in the drawers of which were found papers, letters and formulæ--things giving more than a hint of the use to which Mayes had put his friendship with Mr. Jacob Mason, for of every possible manner and detail in which science--more particularly the science of chemistry--could aid in the commission of crime, there were notes in these same drawers. But most of these things were observed in detail later. The thing that set us once more on the trail of Mayes, that very night and that very hour, was found in the isolated office facing the street. It was a cheque-book, quite full of unused cheques. "This cheque-book," said Hewitt to Inspector Plummer and myself, "was in the drawer below that in which we discovered the Admiralty code. The Eastern Consolidated is the bank, as you see--Upper Holloway branch. Now we must follow this at once, before waiting to search any further. There may be something more important as a clue, or there may not, but at any rate, while we are looking for it we are losing time. This may bring us to him at once." "You mean that he may have some address in Holloway," suggested Plummer, "and we may get it from the bank?"