“How are we to know we’re in the next house but one？”
They decided they would have to go out into the box.room and walk across it taking steps as long as the steps from one rafter to the next. That would give them an idea of how many rafters went to a room. Then they would allow about four more for the passage between the two attics in Polly‘s house， and then the same number for the maid’s bedroom as for the box.room. That would give them the length of the house. When they had done that distance twice they would be at the end of Digory‘s house； any door they came to after that would let them into an attic of the empty house.
“But I don’t expect it‘s really empty at all，” said Digory.
“What do you expect？”
“I expect someone lives there in secret， only coming in and out at night， with a dark lantern. We shall probably discover a gang of desperate criminals and get a reward. It’s all rot to say a house would be empty all those years unless there was some mystery.”
“Daddy thought it must be the drains，” said Polly.