"Yes," said Rollo, "I like to ride, but he don't seem to like to carry me very well. Besides, it is not far now to the top." The path immediately above the pavilion passed out of the region of the vineyards, and entered a little thicket of evergreen trees, through which it ascended by short zigzags, very steep, until at length it came out upon a smooth, grassy mound, which crowned the summit of the elevation; and here suddenly the ruin came into view. It was a single ruined arch, standing alone on the brink of the hill. The arch was evidently, when first built, of the plainest and rudest construction. The stones were of basalt, which is a volcanic rock, very permanent and durable in character, and as hard almost as iron. The mortar between the stones had crumbled away a good deal, but the stones themselves seemed unchanged. Mr. George struck his cane against them, and they returned a ringing sound, as if they had been made of metal. Around this arch were the remains of the ancient wall of the building, by means of which it was easy to see that the whole edifice must have been of very small dimensions, and that it must have been originally constructed in a very rude manner. The arch seems to have been intended for a door or a window. Probably they took more pains with the construction of the arch than they did with the rest of the edifice, using larger and better stones for it, and stronger mortar; and this may be the reason why this part has stood so long, while the rest has fallen down and gone to decay. In fact, it is generally found that the arches of ancient edifices are the parts of the masonry which are the last to fall. The opening in the arch looked down the river. Mr. George took his stand upon the line of the wall opposite the Island of Nonnenwerth, and said that he supposed there must have been another window there. "Here is where the old knight must have stood," said he, "to look down on the island, and the convent where his lost lady was imprisoned." "Yes," said Rollo, "he could look right down upon it from here. I wonder whether the nun knew that he was up here." "Yes," said Mr. George, "there is not the least doubt that she did. They found out some way to have an understanding together, you may depend." After lingering about the old ruin as long as they wished, our travellers came down the hill again as they went up, except that Rollo walked all the way. He was afraid to ride on the donkey going down, for fear that he should fall.