11. In the same manner, when Marseilles was being besieged, and they were pushing forward more than thirty mines, the people of Marseilles, distrusting the entire moat in front of their wall, lowered it by digging it deeper. Thus all the mines found their outlet in the moat. In places where the moat could not be dug they constructed, within the walls, a basin of enormous length and breadth, like a fish pond, in front of the place where the mines were being pushed, and filled it from wells and from the port. And so, when the passages of the mine were suddenly opened, the immense mass of water let in undermined the supports, and all who were within were overpowered by the mass of water and the caving in of the mine.

12. Again, when a rampart was being prepared against the wall in front of them, and the place was heaped up with felled trees and works placed there, by shooting at it with the ballistae red-hot iron bolts they set the whole work on fire. And when a ram-tortoise had approached to batter down the wall, they let down a noose, and when they had caught the ram with it, winding it over a drum by turning a capstan, having raised the head of the ram, they did not allow the wall to be touched, and finally they destroyed the entire machine by glowing fire-darts and the blows of ballistae. Thus by such victory, not by machines but in opposition to the principle of machines, has the freedom of states been preserved by the cunning of architects.

Such principles of machines as I could make clear, and as I thought most serviceable for times of peace and of war, I have explained in this book. In the nine earlier books I have dealt with single topics and details, so that the entire work contains all the branches of architecture, set forth in ten books.

FINIS

SCAMILLI IMPARES (Book III, ch. 4)

No passage in Vitruvius has given rise to so much discussion or been the subject of such various interpretations as this phrase. The most reasonable explanation of its meaning seems to be that of Émile Burnouf, at one time Director of the French School at Athens, published in the Revue Générale del' Architecture for 1875, as a note to a brief article of his on the explanation of the curves of Greek Doric buildings. This explanation was accepted by Professor Morgan, who called my attention to it in a note dated December 12, 1905. It has also quite recently been adopted by Professor Goodyear in his interesting book on Greek Refinements.

Burnouf would translate it nivelettes inégales, "unequal levellers." He states that in many parts of France in setting a long course of cut stone the masons make use of a simple device consisting of three pointed blocks of equal height used as levellers, of which two are placed one at each extremity of the course, while the third is used to level the stones, as they are successively set in place, by setting it upon the stone to be set and sighting across the other two levellers. If two "levellers" of equal height are used with a third of less height placed at the centre of the course, with perhaps others of intermediate height used at intermediate points, it would obviously be equally easy to set out a curved course, as, for instance, the curved stylobate of the Parthenon which rises about three inches in its length of one hundred feet. By a simple calculation any desired curve could be laid out in this way. The word scamillus is a diminutive of scamnum, a mounting-block or bench.

Practically the same explanation is given by G. Georges in a memoir submitted to the Sorbonne in April, 1875. Georges adds an interesting list, by no means complete, of the various explanations that have been offered at different times.

Philander (1522-1552).Projections of the stylobate or pedestals.
Barbaro (1556-1690).The same.
Bertano (1558).Swellings of the die of the stylobate or bosses in the stylobate or the frieze of the entablature.
Baldus (1612).Sub-plinths placed under the bases of the columns.
Perrault (1673-1684).Projection of the stylobate.
Polleni (1739).The same.
Galiani (1758-1790).Projection of the stylobate with hypothesis of embossments on the stylobates and the bases of the columns.
Tardieu and Coussin (1837)
and Mauffras (1847).		Projection of the stylobates.
Aurès (1865).Steps or offsets between the stylobate and the columns.