He felt that, in its petty sphere, the short life of the humble animal before him must have been the prey of crosses and disappointments, as serious to it, as the more severed and destructive afflictions of which he, in his existence, had been the victim; and, as he watched the shadow-like movement of the little fluttering heart of the lizard, he experienced a cruel pleasure in perceiving that there were other beings in the creation, even down to the most insignificant, who inherited a part of his misery, and suffered a portion of his despair.
Ere long, however, his emotions took a sterner and a darker hue. The sight of the animal wearied him, and he flung it contemptuously aside. It disappeared in the direction of the ramparts; and almost at the same moment he heard a slight sound, resembling the falling of several minute particles of brick or light stone, which seemed to come from the wall behind him.
That such a noise should proceed from so massive a structure appeared unaccountable. He rose, and, parting the bushes before him, advanced close to the surface of the lofty wall. To his astonishment, he found that the brickwork had in many places so completely mouldered away, that he could move it easily with his fingers. The cause of the trifling noise that he had heard was now fully explained: hundreds of lizards had made their homes between the fissures of the bricks; the animal that he had permitted to escape had taken refuge in one of these cavities, and in the hurry of its flight had detached several of the loose crumbling fragments that surrounded its hiding-place.
No content, however, with the discovery he had already made, he retired a little, and, looking stedfastly up through some trees which in this particular place grew at the foot of the wall, he saw that its surface was pierced in many places by great irregular rifts, some of which extended nearly to its whole height. In addition to this, he perceived that the mass of the structure at one particular point, leaned considerably out of the perpendicular. Astounded at what he beheld, he took a stick from the ground, and inserting it in one of the lowest and smallest of the cracks, easily succeeded in forcing it entirely into the wall, part of which seemed to be hollow, and part composed of the same rotten brickwork which had at first attracted his attention.
It was now evident that the whole structure, over a breadth of several yards, had been either weakly and carelessly built, or had at some former period suffered a sudden and violent shock. He left the stick in the wall to mark the place; and was about to retire, when he heard the footstep of the sentinel on the rampart immediately above. Suddenly cautious, though from what motive he would have been at that moment hardly able to explain, he remained in the concealment of the trees and bushes, until the guard had passed onward; then he cautiously emerged from the place; and, retiring to some distance, fell into a train of earnest and absorbing thought.
To account to the reader for the phenomenon which now engrossed the Pagan's attention, it will be necessary to make a brief digression to the history of the walls of Rome.
The circumference of the first fortifications of the city, built by Romulus, was thirteen miles. The greater part, however, of this large area was occupied by fields and gardens, which it was the object of the founder of the empire to preserve for arable purposes, from the incursions of the different enemies by whom he was threatened from without. As Rome gradually increased in size, its walls were progressively enlarged and altered by subsequent rulers. But it was not until the reign of the Emperor Aurelian (A.D. 270), that any extraordinary or important change was effected in the defences of the city. That potentate commenced the erection of walls, twenty-one miles in circumference, which were finally completed in the reign of Probus (A.D. 276), were restored by Belisarius (A.D. 537), and are to be seen in detached portions, in the fortifications of the modern city, to the present day.
At the date of our story, then (A.D. 408), the walls remained precisely as they had been constructed in the reigns of Aurelian and Probus. They were for the most part made of brick; and in a few places, probably, a sort of soft sandstone might have been added to the pervading material. At several points in their circumference, and particularly in the part behind the Pincian Hill, these walls were built in arches, forming deep recesses, and occasionally disposed in double rows. The method of building employed in their erection, was generally that mentioned by Vitruvius, in whose time it originated, as 'opus reticulatum'.
The 'opus reticulatum' was composed of small bricks (or stones) set together on their angles, instead of horizontally, and giving the surface of a wall the appearance of a sort of solid network. This was considered by some architects of antiquity a perishable mode of construction; and Vitruvius asserts that some buildings where he had seen it used, had fallen down. From the imperfect specimens of it which remain in modern times, it would be difficult to decide upon its merits. That it was assuredly insufficient to support the weight of the bank of the Pincian Mount, which rose immediately behind it, in the solitary spot described some pages back, is still made evident by the appearance of the wall at that part of the city, which remains in modern times bent out of the perpendicular, and cracked in some places almost from top to bottom. This ruin is now known to the present race of Italians, under the expressive title of 'Il Muro Torto' or, The Crooked Wall.
We may here observe that it is extremely improbable that the existence of this natural breach in the fortifications of Rome was noticed, or if noticed, regarded with the slightest anxiety or attention by the majority of the careless and indolent inhabitants, at the period of the present romance. It is supposed to have been visible as early as the time of Aurelian, but is only particularly mentioned by Procopius, an historian of the sixth century, who relates that Belisarius, in strengthening the city against a siege of the Goths, attempted to repair this weak point in the wall, but was hindered in his intended labour by the devout populace, who declared that it was under the peculiar protection of St. Peter, and that it would be consequently impious to meddle with it. The general submitted without remonstrance to the decision of the inhabitants, and found no cause afterwards to repent of his facility of compliance; for, to use the translated words of the writer above-mentioned, 'During the siege neither the enemy nor the Romans regarded this place.' It is to be supposed that so extraordinary an event as this, gave the wall that sacred character, which deterred subsequent rulers from attempting its repair; which permitted it to remain crooked and rent through the convulsions of the middle ages; and which still preserves it, to attest the veracity of historians, by appealing to the antiquarian curiosity of the traveller of modern times.
We now return to Ulpius. It is a peculiarity observable in the characters of men living under the ascendancy of one ruling idea, that they intuitively distort whatever attracts their attention in the outer world, into a connection more or less intimate with the single object of their mental contemplation. since the time when he had been exiled from the Temple, the Pagan's faculties had, unconsciously to himself, acted solely in reference to the daring design which it was the business of his whole existence to entertain. Influenced, therefore, by this obliquity of moral feeling, he had scarcely reflected on the discovery that he had just made at the base of the city wall, ere his mind instantly reverted to the ambitious meditations which had occupied it in the morning; and the next moment, the first dawning conception of a bold and perilous project began to absorb his restless thoughts.