So we did. We had a most refreshing game. It was exactly like Denny to be the one who slipped down behind the barrels, and did not break a single one of all his legs or arms. "No," he cried, in answer to our anxious inquiries. "I'm not hurt a bit, but the wall here feels soft--at least not soft--but it doesn't scratch your nails like stone does, so perhaps it's the door of a secret dungeon or something like that." "Good old Dentist!" replied Oswald, who always likes Denny to have ideas of his own, because it was us who taught him the folly of white-mousishness. "It might be," he went on, "but these barrels are as heavy as lead, and much more awkward to collar hold of." "Couldn't we get in some other way?" Alice said. "There ought to be a subterranean passage. I expect there is if we only knew." Oswald has an enormous geographical bump in his head. He said-- "Look here! That far cellar, where the wall doesn't go quite up to the roof--that space we made out was under the dining-room--I could creep under there. I believe it leads into behind this door." "Get me out! Oh do, do get me out, and let me come!" shouted the barrel-imprisoned Dentist from the unseen regions near the door. So we got him out by Oswald lying flat on his front on the top barrel, and the Dentist clawed himself up by Oswald's hands while the others kept hold of the boots of the representative of the house of Bastable, which, of course, Oswald is, whenever Father is not there. "Come on," cried Oswald, when Denny was at last able to appear, very cobwebby and black. "Give us what's left of the matches!" The others agreed to stand by the barrels and answer our knocking on the door if we ever got there. "But I daresay we shall perish on the way," said Oswald hopefully. So we started. The other cellar was easily found by the ingenious and geography-bump-headed Oswald. It opened straight on to the moat, and we think it was a boathouse in middle-aged times. Denny made a back for Oswald, who led the way, and then he turned round and hauled up his inexperienced, but rapidly improving, follower on to the top of the wall that did not go quite up to the roof. "It is like coal mines," he said, beginning to crawl on hands and knees over what felt like very prickly beach, "only we've no picks or shovels." "And no Sir Humphry Davy safety lamps," said Denny in sadness. "They wouldn't be any good," said Oswald; "they're only to protect the hard-working mining men against fire-damp and choke-damp. And there's none of those kinds here." "No," said Denny, "the damp here is only just the common kind." "Well, then," said Oswald, and they crawled a bit further still on their furtive and unassuming stomachs. "This is a very glorious adventure. It is, isn't it?" inquired the Dentist in breathlessness, when the young stomachs of the young explorers had bitten the dust for some yards further.