No sooner had Betty entered it than she gave a little cry and stood staring at the end wall, where a sort of picture in mosaic work was hanging, filling up its whole space. “That was in the villa that belonged to Lucius!” she exclaimed. “I remember it quite well. It was the pavement of one of the rooms. There’s the lady riding on that funny animal’s back with the border round her, just as I saw it. Oh, Godmother! Just fancy its being here after all these years and years.” “It _is_ wonderful,” said Godmother. “How many of the thousands of people who every day hurry along the streets near London Bridge either know or remember that deep down under their feet lies a buried Roman city? Every now and then a fragment of it, like this one, is dug up. But there must be much, much more hidden far beneath houses and shops and roads where trams and omnibuses roll and rattle. By the way,” she added, “if you want to see the _actual_ piece of pavement that was in the villa ‘that belonged to Lucius’ we shall have to go to the British Museum. This one is only a copy of it.” “I shall go one day,” Betty answered. “I should like to see the _very_ pavement I walked on. I’m luckier than any of the children in London,” she added with a little chuckle of delight. “Now look at some of the things in these cases,” advised Godmother. “You will find them just as interesting.” Betty obediently examined the contents of one of the glass boxes the room contained, and soon found occasion for a fresh excitement. On a label beside a collection of battered coins, she read: _Found in the river bed near the present London Bridge._ Instantly a scene rose in her mind of a little fair-haired girl crying and looking down through the chinks of a wooden bridge into the shining water. “Oh, Godmother, perhaps one of them is the very coin that poor little girl dropped when her mother was so angry with her?” she cried. “Perhaps,” said Godmother. “She dropped it one thousand five hundred years ago, and that’s about the date of this group of coins.” “How do people know that?” “By the inscriptions on them, we discover which emperor was ruling in Rome, and in that way we are often able to fix the date at which the money was in use.” In another moment Betty had discovered other things in the cases which took her thoughts back to the “magic” experience. These were ornamental pins for the hair, combs, and other toilet articles which must once have been pretty and shining, but were dull and rusty now from long burial in the earth. She thought of the glimpse she had had of a bedroom (perhaps belonging to the mother of Lucius), in which such things as these were lying on a marble table. In fact, everything she saw in the cases reminded her of Roman London, with its beautiful villas and gardens, now buried and almost as forgotten as though they had never existed. And she sighed. “It’s very sad to think of,” she said.