B 0 
K. X. 
The tabulae (AC and BD) that are at the top and bottom of the capitule, and are called 
parastae AB; and then the two epizyges IK were turned 
it), the diostra was drawn back again by means of the 
about, so as to twist the cords with great violence: by this 
lucula, which was turned round by two men, with the 
means the arm NO was held fast, and caused to press 
assistance of levers L put through each end of the same; 
backward with great force against the face of the parasta 
and thus the arms I were drawn and strained: this being 
AB, where it entered a semicircular excavation R, made 
done sufficiently, the arrow KH was then laid in the epi¬ 
there to receive it. The same operation was repeated on 
toxis, and discharged in the manner before described. 
the other side of the capitule with the epizygis L and M. 
The larger engines of this kind, in which the powet 
and the arm PQ; and the two arms thus held by the 
twisted cords of sinews acquired a great degree of elastic 
power, and answered the purpose of the bow in the be- 
fore-described scorpion. 
Through holes made at the ends O and Q of the arms 
was put the bow-string OQ, which was a cord of sinews 
of the strongest texture; and was of such a length as to 
sustain the arms at a little distance from the parastae, that 
in their recoiling they might not strike against those mem- 
bers, and be thereby damaged: or a cushion was sometimes 
placed there for that purpose. The arms were called 
brachia and ancones; the complication or column IK of 
twisted cords that held the arms was called bemitonus, and 
sometimes unitonus. The interval FH between the two 
hemitones was left for the syrinx and diostra, formed as in 
the scorpions; the end of the syrinx being firmly fixed 
upon the upper surface S of the lower scutula or peritreta. 
Heron describes another capitule, with some but with 
no material difference: the scutula or peritreta being made 
in shape like a semi-octagon ABCDEF, Fig. XCVI, so 
that it was broader in the middle than at the ends; and the 
two mesostae GE and HD were consequently broadet than 
the two parastae AF and BG; the breadth of each being 
determined by the intersection of the inner sides Tand K 
of the parastae, and the outer sides E and D of the mesostae, 
with the semicircle AIEDKB, as shewn by the figure. 
Fig. XCVII. 
To the capitule AA, thus formed, was fixed, as before 
laid, one end of the syrinx B, being, with the diostra CH, 
chira and schasteria D, and cataclida O, made in all re¬ 
spects the same as before described in the scorpion, but 
without the catagogis; instead of which a sucula or wind- 
lals E was connected to the other end of the syrinx, whose 
iides F projected forward in order to receive it. To the 
middle part G of this sucula, between the two sides of the 
syrinx, was fixed a cord GC, extending from thence to the 
end C'of the diostra, where it was fastened to a hook; 
when therefore the machine was prepared as described in 
the scorpion (that is to say, the diostra pushed forward 
till the chira arrived at the bow-string IKI, and hooked 
was very great, were drawn by pulleys in various combi¬ 
nations, or with pulleys and suculae connected together: 
and instead of the simple iron axons, or epizyges, that sus¬ 
tained the tonus of cords, the machines M, called by Vi¬ 
truvius modiols, and by Heron choenices, were used; and 
which will be explained in the description of the Balistae. 
This engine being too large and heavy to be managed 
in the hand, and being required to be turned and elevated 
in different directions, it became necessary to support it 
on a base that should afford the required conveniences. 
This base was thus constructed: 
A post N (or columella, as Vitruvius calls it), about 
two feet and a quarter high, was fixed upright upon a three- 
legged base PQR, and supported by three braces 888 
on the same. At the top of the columella was a cylindric 
tenon T, on which turned the chalchesium U, a, V, which 
was formed thus:—On a horizontal rectangular board UV 
two perpendicular rectangular sides Ua, and Vb, were fixed 
to the right and left; and between these was another hori- 
zontal board bed, a little above the former. 
Through the middle of the two horizontal boards holes 
capable of receiving the tenon T of the columella were 
bored. The two perpendicular sides were so far apart as 
to admit between them the breadth of the syrinx; which 
being introduced, an iron axis e passed horizontally 
through the sides of the chalchesium and those of the 
syrinx, connecting them together, and admitting the 
syrinx to turn vertically on the said axis: so that the 
whole catapulta could be elevated and declined to any 
direction: and, by the chalchesium turning on the tenon 
of the columella, it could also be turned horizontally to 
any direction required, and by these means be pointed 
against any intended object. 
To keep it steadily fixed when thus directed, one end / 
of a piece of timber f'g was annexed to the top of the 
columella, by a joint that admitted it to turn horizontally; 
so that the other end g, resting on the ground, might be 
placed in different situations. This piece was called ante¬ 
ridium; near to the upper end of which the anapausteria, hi, 
was annexed, with a joint admitting it to be elevated and 
declined. When therefore the syrinx was set to its re-