should be fitted to a balista, for the great power necessary to work
the engine was easily procured from skeins of twisted cord; a simpler,
much more compact and infinitely lighter method of giving the weapon its
projectile force, than fixing to its framework a huge and cumbersome bow
in one piece.
Judging from models I have made and from the writings of the ancients,
the range of a large balista was from 400 to 450 yards.
The power of a full-sized balista, such as the one shown in fig. 204,
p. 300. was immense. The skeins of twisted hair or sinew between which
its arms worked, were each about 8 in. thick. The aggregate motive energy
of these skeins was, therefore, equal to one skein of 16 in. diameter.
Now a catapult with a skein of 16 in. was able to throw a stone weighing
from 20 to 30 lbs. from 350 to 400 yards. In the balista there was the
same amount of contained force as in the catapult alluded to. In the balista,
however, the whole power of the engine was exerted to cast a comparatively
light missile, in the form of a javelin of 8 to 10 Lbs. weight.1
From these considerations it is evident what a terrible weapon the balista
must have been when its javelin or huge arrow fell among the ranks of an
As balistas were much lighter and more portable than catapults, they
often represented the field artillery of an army on the march. Catapults
of large size were too heavy for transport over rough ground and were essentially
Balistas were equally adapted for sieges and for open warfare.
We read of the javelin of a balista piercing through several men, and
on another occasion of one of its javelins nailing a man in armour to a
tree, p. 271.
This is easily understood when we consider the power of the engine and
the distance it was able to throw its steel-tipped projectile.
The balista had an advantage over the catapult in that it was able to
cast its missile at a much lower elevation. The balista could be aimed
in any direction, and its trajectory could be quickly altered by a couple
of men raising or lowering its stock. On the other hand, the ponderous
framework of the catapult often had first to be lifted with levers by about
a dozen men, and then propped up beneath its ends with wedges to regulate
the flight of its stone.
In this way the catapult was fixed for perhaps an entire day so as to
1 My largest model of a balista has arms only
2 ft. long and skeins of cordage but 3 in. thick. It will, however, project
a javelin in the form of a heavy arrow weighing 2 1/2 Lbs., to a range
of 300 yards.