From Estremoz to Elvas the distance is six leagues. I started at nine next morning; the first part of the way lay through an inclosed country, but we soon emerged upon wild bleak downs, over which the wind, which still pursued us, howled most mournfully. We met no one on the route; and the scene was desolate in the extreme; the heaven was of a dark grey, through which no glimpse of the sun was to be perceived. Before us, at a great distance, on an elevated ground, rose a tower—the only object which broke the monotony of the waste. In about two hours from the time when we first discovered it, we reached a fountain, at the foot of the hill on which it stood; the water, which gushed into a long stone trough, was beautifully clear and transparent, and we stopped here to water the animals. Having dismounted, I left the guide, and proceeded to ascend the hill on which the tower stood. Though the ascent was very gentle, I did not accomplish it without difficulty; the ground was covered with sharp stones, which, in two or three instances, cut through my boots and wounded my feet; and the distance was much greater than I had expected. I at last arrived at the ruin, for such it was. I found it had been one of those watch-towers or small fortresses called in Portuguese _atalaias_; it was square, and surrounded by a wall, broken down in many places. The tower itself had no door, the lower part being of solid stonework; but on one side were crevices at intervals between the stones, for the purpose of placing the feet, and up this rude staircase I climbed to a small apartment, about five feet square, from which the top had fallen. It commanded an extensive view from all sides, and had evidently been built for the accommodation of those whose business it was to keep watch on the frontier, and at the appearance of an enemy to alarm the country by signals—probably by a fire. Resolute men might have defended themselves in this little fastness against many assailants, who must have been completely exposed to their arrows or musketry in the ascent.