MONEY VALUE OF THE BARRIER.
The Wall is sixty-eight miles long; granting that it was only sixteen feet high, but had a continuous thickness of eight feet, we have 1,702,115 cubic yards of masonry, to say nothing of stations, mile-castles, and turrets.
Twelve shillings per cubic yard is as near as may be the present value of masonry, such as that of which the Roman Wall consists—the cost of this part of the structure would therefore be 1,021,269l.
Taking into account that the labour was forced, each cubic yard of the Wall would, at the least, require, in quarrying the stone, its carriage to the Wall, its setting, and other operations, one entire day’s exertions of one man. In this way we have 1,702,115 days’ labour in the stone Wall.
Taking the north fosse at the dimensions already given, its excavation would involve the removal of 5,585,072 cubic yards. A modern excavator, stimulated by pay proportioned to his work, enjoying food, and raiment, and shelter, such as the ancient Briton was a stranger to, and possessing the advantage of good tools, and good organization, can remove the enormous quantity of twenty cubic yards of earth per day. The labourer, driven to his ungrateful task by a Roman task-master, and compelled to support himself as best he might, and to labour with tools of the rudest construction, would not accomplish the half of this task; the removal of eight yards per diem would probably be an average day’s work. The excavation of the north fosse would thus, under these circumstances, involve 698,134 days’ labour. At the present time, when twenty cubic yards may be removed per man in a day, and when a day’s wages may be set down at half-a-crown, the whole cost of the excavation of the fosse would be 34,906l.
In this estimate no account has been taken of the increased labour occasioned by cutting through the rocks that are sometimes met with. The entire absence of the ditch, however, in the hilly district, compensates for this omission.
The fosse of the Vallum is rather less than that of the Wall. Making a deduction of one-third on this account, and supposing that the distance which the Vallum falls short of the Wall at each extremity, makes amends for the increased labour of cutting through the rocky ground, we have 3,723,382 cubic yards to be removed, involving 465,422 days of forced labour. The whole could now be done for the sum of 23,271l. No account is taken of the labour expended in raising the earthen ramparts, or the cost of their construction, for the reason, that the removal of the earth from the fosse implied its being deposited somewhere; no place would be more convenient for this purpose than the mounds of the rampart.
TIME REQUIRED FOR ITS CONSTRUCTION.
Adding together these results, we find that the cost of the Wall and its north fosse would be 1,056,175l., and that the cost of the Vallum, added to this would form a total of 1,079,446l. The number of days’ labour involved in the Wall would be 2,400,249, and, adding to this, that of the Vallum, we have for the whole 2,865,671 days’ labour.
The largest number of men that we can conceive to be brought to bear at once upon the Wall, including such of the Roman troops as could be spared from military operations, is ten thousand. This body, at the rate already supposed, would, by continuous labour, execute the Wall and its ditch in 240 days, and, taking the Vallum also into account, in 286 days. In the exposed district over which the Wall runs, it is not probable that the weather would allow of the work being pursued during more than two hundred days in the year. If, in addition to this, we make deductions for the chances of war, two years may be stated as the shortest time in which the whole of the works could be executed.