s of the "table," one half of a hole.

7. The shafts of the "ladder" are thirteen holes in length, one hole in
thickness; the space between them is one hole and a quarter in breadth,
and one and one eighth in depth. Let the entire length of the ladder on
its upper surface--which is the one adjoining the arms and fastened to
the table--be divided into five parts. Of these let two parts be given
to the member which the Greeks call the [Greek: chelonion], its breadth
being one and one sixth, its thickness one quarter, and its length
eleven holes and one half; the claw projects half a hole and the
"winging" three sixteenths of a hole. What is at the axis which is
termed the... face... the crosspieces of three holes?

8. The breadth of the inner slips is one quarter of a hole; their
thickness one sixth. The cover-joint or lid of the chelonium is
dove-tailed into the shafts of the ladder, and is three sixteenths of a
hole in breadth and one twelfth in thickness. The thickness of the
square piece on the ladder is three sixteenths of a hole,... the
diameter of the round axle will be equal to that of the claw, but at the
pivots seven sixteenths of a hole.

9. The stays are... holes in length, one quarter of a hole in breadth at
the bottom, and one sixth in thickness at the top. The base, termed
[Greek: eschara], has the length of... holes, and the anti-base of four
holes; each is one hole in thickness and breadth. A supporter is jointed
on, halfway up, one and one half holes in breadth and thickness. Its
height bears no relation to the hole, but will be such as to be
serviceable. The length of an arm is six holes, its thickness at the
base two thirds of a hole, and at the end one half a hole.

I have now given those symmetrical proportions of ballistae and
catapults which I thought most useful. But I shall not omit, so far as I
can express it in writing, the method of stretching and tuning their
strings of twisted sinew or hair.

CHAPTER XII

THE STRINGING AND TUNING OF CATAPULTS

1. Beams of very generous length are selected, and upon them are nailed
socket-pieces in which windlasses are inserted. Midway along their
length the beams are incised and cut away to form framings, and in these
cuttings the capitals of the catapults are inserted, and prevented by
wedges from moving when the stretching is going on. Then the bronze
boxes are inserted into the capitals, and the little iron bolts, which
the Greeks call [Gr