So long as they keep their caps on their heads the dwarfs are invisible; but if any one can get possession of a dwarf's cap he can see them, and becomes their master. This is the foundation of one of the best of the dwarf stories--the story of John Dietrich, who went out to the sandhills at Ramfin, in the isle of Rugen, on the eve of St. John, a very, very long time ago, and managed to strike off the cap from the head of one of the brown dwarfs, and went down with them into their underground dwelling-place. This was quite a little town, where the rooms were decorated with diamonds and rubies, and the dwarf people had gold and silver and crystal table-services, and there were artificial birds that flew about like real ones, and the most beautiful flowers and fruits; and the dwarfs, who were thousands in number, had great feasts, where the tables, ready spread, came up through the floor, and cleared themselves away at the ringing of a bell, and left the rooms free for dancing to the strains of the loveliest music. And in the city there were fields and gardens, and lakes and rivers; and instead of the sun and the moon to give light, there were large carbuncles and diamonds which supplied all that was wanted. John Dietrich, who was very well treated, liked it very much, all but one thing--which was that the servants who waited upon the dwarfs were earth children, whom they had stolen and carried underground; and amongst them was Elizabeth Krabbin, once a playmate of his own, and who was a lovely girl, with clear blue eyes and ringlets of fair hair. John Dietrich of course fell in love with Elizabeth, and determined to get her out of the dwarf people's hands, and with her all the earth children they held captive. And when he had been ten years underground, and he and Elizabeth were grown up, he demanded leave to depart, and to take Elizabeth. But the dwarfs, though they could not hinder him from going, would not let her go, and no threats or entreaties could move them. Then John Dietrich remembered that the little people cannot bear an evil smell; and one day he happened to break a large stone, out of which jumped a toad, which gave him power to do what he pleased with the dwarfs, for the sight or smell of a toad causes them pain beyond all bearing. So he sent for the chiefs of the dwarfs, and bade them let Elizabeth go. But they refused; and then he went and fetched the toad. Then the story goes on in this way:--