They were now on the outskirts of the undulating plain, on which a rich soil overlying the granite rocks extends from Evora southward to the city of Beja. The signs of cultivation and population multiplied as they went on. The fields became larger and more frequent; detached farm houses were seen on either hand, and they fell in on the road with many peasants riding large and spirited asses, or driving oxen all light bays with enormous horns, and so sleek and well grown, that the commissary gazed on them with admiring eye and watering mouth, and pronounced them equally fit for the yoke or the shambles. It was a relief to find themselves once more in a cultivated country, and Lady Mabel gazed round, admiring the prospect. "There is," she observed, "one drawback to the landscape. At home, one of the most enlivening features in our rural scenes, are the white sheep scattered on the hills, but here they are almost black." "But the goats you see are generally white," answered L'Isle. "It is, too, the more picturesque animal, and well supplies what is wanting in the sheep." Evora was at hand. L'Isle launched out into an erudite discourse on the aqueduct of Sertorius, which, stretching its long line of arches from the neighboring hills, was converging with their road to the city. As they entered it he was giving Lady Mabel all the pros and cons, as to whether it was really the work of that redoubtable Roman. The commissary was luxuriously anticipating the shade and rest before him, when to his surprise and regret, L'Isle led the party another way, and halted them before a small but striking building, which here crowned the aqueduct at its termination in the city. "Look, Lady Mabel. Observe it well, Mrs. Shortridge. This castellum is a miniature embodiment of Roman taste and skill in architecture. This is no ruin calling upon the imagination to play the hazardous part of filling up the gaps made by the hand of time. We see it as the Moor, the Goth, the Roman saw it, save the loss of a few vases which adorned the depressed parapet, and the scaling plaster which here and there betrays that the builder used that cheap but immortal material, the Roman brick." Much did Lady Mabel admire this architectural gem, scarcely tarnished by the elements in nineteen centuries, and much more would L'Isle have found to say of it, when the commissary, impatiently fanning himself with his hat, ventured to ask, "how much longer shall we stay broiling in the noon-day sun, staring at this Roman sentry-box?" "Sentry-box!" said Mrs. Shortridge, with a puzzled air, "were the Romans a gigantic people?" "There were giants in those days," said Lady Mabel, gravely, gazing on the castellum. But a crowd of idlers and beggars began to collect around the cavalcade, and turning, they rode off, and were soon enjoying the shelter, if not the more substantial hospitality, of the _Estalagem de San Antonio_. CHAPTER X.