"It is just the sort of hidden mare’s nest about which one has bad dreams when putting one’s money in a Bank," Saturn reflected, at a moment when he and Daniel were several convolutions behind Mr. Ham and Monsieur Kohan. But a moment later they caught up to find William Ham looking a bit huffy. He was directing their attention to a Gothik arch sealed off by a new portcullis of iron bars. Pyramidal beams of lanthorn-light, shining through the interstices, careered around the space on the other side. Slivers of gold and silver winked between the planks of crates. "The inherited complexities of the property," said Mr. Ham, "are, as you can see, giving way to a steady programme of rationalization. Where weaknesses are found, they are made strong. Several entire chambers have been infilled. Where sound vaults are discovered, they are fortified, as here." Mr. Ham then took them on a lengthy detour intended to bolster these and other assertions with evidence visual and anecdotal. By this point Daniel could no more have made his way out to the street than he could have balanced the Bank’s accounts on his fingers. But he did feel that they were on average descending, for the air got damper and colder as they went, and the architecture changed. There was less wood, and what there was of it was rotten, and being replaced by masonry. They passed through a Gothik stratum into a Romanesque, or perhaps Roman—boundaries were ambiguous, as the site might have gone unchanged for half a millennium after the Romans had pulled out. Evidence of dampness was all round, though actual standing water was rare. It looked, in other words, as though they had found a way to channel groundwater and drain it out of the place—probably to Walbrook, a local creek that was famous because, at some point after the Fall of Rome, it had gone missing.