On Architecture

4. He also employed the ram mounted on wheels, an account of which he left in his writings. As for the tower, he says that the smallest should be not less than sixty cubits in height and seventeen in breadth, but diminishing to one fifth less at the top; the uprights for the tower being nine inches at the bottom and half a foot at the top. Such a tower, he says, ought to be ten stories high, with windows in it on all sides.

5. His larger tower, he adds, was one hundred and twenty cubits high and twenty-three and one half cubits broad, diminishing like the other to one fifth less; the uprights, one foot at the bottom and six digits at the top. He made this large tower twenty stories high, each story having a gallery round it, three cubits wide. He covered the towers with rawhide to protect them from any kind of missile.