Jack tried to nap, but it was the middle of the afternoon and he could not sleep with Paris happening all around him. So he set out across the roof-tops, memorizing the turns he'd take, the leaps he'd make, the crevices he'd hide in, the places he'd stand and fight, if the Lieutenant of Police ever came for him. This led to his tromping over numerous roof-tops, setting off great commotions and panics among many garret-dwellers who lived in fear of raids. Mostly he had the roof-tops to himself. There were a few Vagabondish-looking children moving in packs, and a large number of roof-rats. On almost every block there were tattered ropes, or frail tree-branches, bridging gaps over streets, not strong enough for humans, but enthusiastically used by rats. In other places the ropes lay coiled neatly on roofs, the sticks rested in rain-gutters. Jack reckoned that they must have been put up by St.-George, who used them to channel and control the migrations of rats, as a general might tear down bridges in one part of a disputed territory while improvising new ones elsewhere.