But if instead of this peaceful scene the wrong half of the past were to appear! For there were times when the heavy booming and uproar drew ever nearer from without, and then the faces of the señoritas as they peered through the elaborate bars were ashy pale. There were moments, too, when the last doubts had turned to a bitter certainty, when the forms of fleeing men passed the house, and those of others, who stayed, reddened the ground before the door. And last of all!--the apparition of the strange men in hostile garb, the lust of slaughter in their eyes as they rushed on, making another place of the once familiar street. Thirsting for blood, hungry for booty, and for all things beyond--the cheeks of the shuddering señoritas have not paled without reason. After all, perhaps it is better to leave undisturbed the knocker upon the old door. Such mental apparitions, moreover, could be multiplied indefinitely, for there are a dozen houses of similar design, if of varied ruinous importance, in the town. Indeed, the place breathes strongly of the past. At a street corner here and there is an ancient cannon, buried muzzle upwards into the ground, that serves to fend off from the sidewalk such wheeled traffic as exists. After a while the narrow street falls away, and the wide sweep of the plaza extends to the front. The place was once the site of a rather peculiar feat of frontier delimitation. The occasion was that of one of the numerous cessions by treaty to Portugal of the town that the Spaniards were wont to win by force of arms. On receiving the order from the Court of Spain to evacuate the province in favour of the temporarily reconciled enemy the staunch old Spanish Governor lost patience. The town, he knew full well, he must surrender, but he refused to give up more even at the command of his royal master. So he raised the muzzle of a cannon in the plaza, fired a shot to right and left, and told the Portuguese that the land within the range of the balls was theirs, but no more. And with this they had to be content. There are now no cannon in the plaza, where, indeed, the wild shrubs and grasses alone thrive. Passing across it, the river is approached again, for Colonia covers a small promontory. Ere reaching the water on the farther side, however, it is necessary to pass by far the most imposing ruin in the place. By the side of the white lighthouse tower a tall fragment of grey fortress wall rears itself aloft. Some four feet thick throughout, its crumbling embrasures are strongly lit up by the blue sky behind.