APPENDIX TO THE HISTORICAL CONSTRUCTION

OF WALLS.

THE question is often asked, and is a very natural one, "How were the large blocks of stone, each a ton weight, brought from the quarries and raised to a height of sometimes fifty feet from the ground, and fixed in walls twelve feet thick ?" This requires some explanation. The quarries of tufa were sometimes close at hand. The hills of Rome consist of tufa, and in cutting trenches through them. the blocks of stone cut out were used at once for building walls to support the earth in a vertical position where there was no rock. The original settlers on the Palatine probably had no need to go further for their stone than the great trench across the middle of the hill, on the south side of Roma Quadrata, and the ledge round it at the foot of the wall and on which the wall stood, as we have seen well illustrated in the Wall of the Latins on the Aventine, where the same plan was adopted. A terrace or platform was cut at the level necessary for a road at the foot of the wall, with a second scarped cliff outside of it, forming a second line of defence. Below that was

the great foss, also probably cut out of the tufa rock, unless they had got down below it into the clay under it. Each of the other hills, when originally inhabited, was therefore also fortified, for no habitation was safe in those days unless protected by walls.

After this, quarries were made at the nearest and most convenient points; a large one has been found just to the north of the Prætorian Camp, outside of the walls, but there are subterranean quarries still in use in several of the hills, and remains of many other similar ancient quarries. To move these large blocks from the quarries they were placed on a number of small wooden rollers, and pushed along by manual labour only,-just as large blocks of marble are now pushed along upon the Marmorata or marble-wharf, -through the streets, until they are placed upon carts; but as each cart could only take one stone, "each stone was a load for a cart," as we are expressly told by Dionysius, land-carriage for stone must have been very expensive, that is, it required a great deal of men's time, and time is equivalent to money.

For this reason it does not pay to bring these stones from any great distance in carts. Water carriage is always much cheaper than any other, therefore quarries were made at the most convenient places on the banks of the river Anio, and very fine old quarries remain

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Appendix to the Historical Construction of Walls.

a few miles up the river at the place now called the "Caves of Cervaro," and the "Caves of the Appia," about half-a-mile higher up, in which one of the springs of the Aqua Appia is situated. The stones were floated down the river on rafts, just as is done on the Rhine now; and the timber of which the rafts were made was good for building purposes also, or some of it for firewood only, but always worth enough to make the carriage of the stone cost very little.

When it arrived at the foot of the wall where it was to be used, there were two modes of raising it to the height required. One was merely pushing them up on inclined planes, sometimes on artificial banks of earth, such as the great agger of Servius Tullius, where the wall was built simultaneously with the raising of the bank, of which it formed the outer facing. I am informed by officers of the AngloIndian army that in some parts of India, where similar buildingmaterial is found, this primitive mode of building is still used as the cheapest, and manual labour being very abundant, a bank of earth is made up against the wall, which is raised higher as the wall is raised, and remains behind it as part of the fortification. On the hills also the terrace, ledge, or platform before mentioned was not level, but had a very gradual slope, which formed the zigzag road up to the summit. The blocks of stone could therefore easily be pushed up to the foot of the wall, but to raise them to the top of a high wall another contrivance was required, and of this we fortunately have a representation on a sculpture on the tomb of the Aterii of the first century of the Christian era, but probably representing also a far more ancient custom. This is a kind of gigantic crane, very much resembling a modern fire escape, excepting that in the place of wheels only, we have a tread-wheel, with several men inside of it; as they walked up the incline they raised the end of the crane with the heavy stone attached to it. Steps are made up the crane, which serves as a ladder for two men to go up and fix the stone in its place. This done, the end of the crane is suffered to descend gradually to the ground, and the operation is repeated. In the sculpture two men are represented fixing a stone on the corner of a temple (?), or of a tomb, or some large building of considerable height, judging by the proportion of the size of the men, who look like pigmies at work upon it. This sculpture is represented in our photograph, No. 1500.