The Ten Books on Architecture
tortoise. Inside of this was set the machinery of the ram, termed in
Greek [Greek: kriodochê], in which was placed a roller, turned on a
lathe, and the ram, being set on top of this, produced its great
effects when swung to and fro by means of ropes. It was protected, like
the tower, with rawhide.
7. He explained the principles of the borer as follows: that the machine
itself resembled the tortoise, but that in the middle it had a pipe
lying between upright walls, like the pipe usually found in catapults
and ballistae, fifty cubits in length and one cubit in height, in which
a windlass was set transversely. On the right and left, at the end of
the pipe, were two blocks, by means of which the iron-pointed beam,
which lay in the pipe, was moved. There were numerous rollers enclosed
in the pipe itself under the beam, which made its movements quicker and
stronger. Numerous arches were erected along the pipe above the beam
which was in it, to hold up the rawhide in which this machine was
enveloped.
8. He thought it needless to write about the raven, because he saw that
the machine was of no value. With regard to the scaling machine, termed
in Greek [Greek: epibathra], and the naval contrivances which, as he
wrote, could be used in boarding ships, I have observed that he merely
promised with some earnestness to explain their principles, but that he
has not done so.
I have set forth what was written by Diades on machines and their
construction. I shall now set forth the methods which I have learned
from my teachers, and which I myself believe to be useful.
CHAPTER XIV
THE TORTOISE
1. A tortoise intended for the filling of ditches, and thereby to make
it possible to reach the wall, is to be made as follows. Let a base,
termed in Greek [Greek: eschara], be constructed, with each of its sides
twenty-one feet long, and with four crosspieces. Let these be held
together by two others, two thirds of a foot thick and half a foot
broad; let the crosspieces be about three feet and a half apart, and
beneath and in the spaces between them set the trees, termed in Greek
[Greek: hamaxopodes], in which the axles of the wheels turn in iron
hoops. Let the trees be provided with pivots, and also with holes
through which levers are passed to make them turn, so that the tortoise
can move forward or back or towards its right or left side, or if
necessary obliquely, all by the turning of the trees.
2. Let two beams be laid on the base, projecting for six feet on each
side, round the projections of which let two other beams be nailed,
projecting seven feet beyond the former, and of the thickness and
breadth prescribed in the case of the base. On this framework set up
posts mortised into it, nine feet high exclusive of their tenons, one
foot and a quarter square, and one foot and a half apart. Let the posts
be tied together at the top by mortised beams. Over the beams let the
rafters be set, tied one into another by means of tenons, and carried up
twelve feet high. Over the rafters set the square beam by which the
rafters are bound together.
3. Let the rafters themselves be held together by bridgings, and covered
with boards, preferably of holm oak, or, this failing, of any other
material which has the greatest strength, except pine or alder. For
these woods are weak and easily catch fire. Over the boardings let there
be placed wattles very closely woven of thin twigs as fresh as possible.
Let the entire machine be covered with rawhide sewed together double and
stuffed with seaweed or straw soaked in vinegar. In this way the blows
of ballistae and the force of fires will be repelled by them.
CHAPTER XV
HEGETOR'S TORTOISE
1. There is also another kind of tortoise, which has all the other
details as described above except the rafters, but it has round it a
parapet and battlements of boards, and eaves sloping downwards, and
is covered with boards and hides firmly fastened in place. Above this
let clay kneaded with hair be spread to such a thickness that fire
cannot injure the machine. These machines can, if need be, have eight
wheels, should it be necessary to modify them with reference to the
nature of the ground. Tortoises, however, which are intended for
excavating, termed in Greek [Greek: oryktides], have all the other
details as described above, but their fronts are constructed like the
angles of triangles, in order that when missiles are shot against them
from a wall, they may receive the blows not squarely in front, but
glancing from the sides, and those excavating within may be protected
without danger.
2. It does not seem to me out of place to set forth the principles on
which Hegetor of Byzantium constructed a tortoise. The length of its
base was sixty-three feet, the breadth forty-two. The corner posts, four
in number, which were set upon this framework, were made of two timbers
each, and were thirty-six feet high, a foot and a quarter thick, and a
foot and a half broad. The base had eight wheels by means of which it
was moved about. The height of these wheels was six and three quarters
feet, their thickness three feet. Thus constructed of three pieces of
wood, united by alternate opposite dovetails and bound together by
cold-drawn iron plates, they revolved in the trees or amaxopodes.
3. Likewise, on the plane of the crossbeams above the base, were erected
posts eighteen feet high, three quarters of a foot broad, two thirds of
a foot thick, and a foot and three quarters apart; above these, framed
beams, a foot broad and three quarters of a foot thick, held the whole
structure together; above this the rafters were raised, with an
elevation of twelve feet; a beam set above the rafters united their
joinings. They also had bridgings fastened transversely, and a flooring
laid on them protected the parts beneath.
4. It had, moreover, a middle flooring on girts, where scorpiones and
catapults were placed. There were set up, also, two framed uprights
forty-five feet long, a foot and a half in thickness, and three quarters
of a foot in breadth, joined at the tops by a mortised crossbeam and by
another, halfway up, mortised into the two shafts and tied in place by
iron plates. Above this was set, between the shafts and the crossbeams,
a block pierced on either side by sockets, and firmly fastened in place
with clamps. In this block were two axles, turned on a lathe, and ropes
fastened from them held the ram.
5. Over the head of these (ropes) which held the ram, was placed a
parapet fitted out like a small tower, so that, without danger, two
soldiers, standing in safety, could look out and report what the enemy
were attempting. The entire ram had a length of one hundred and eighty
feet, a breadth at the base of a foot and a quarter, and a thickness of
a foot, tapering at the head to a breadth of a foot and a thickness of
three quarters of a foot.
6. This ram, moreover, had a beak of hard iron such as ships of war
usually have, and from the beak iron plates, four in number, about
fifteen feet long, were fastened to the wood. From the head to the very
heel of the beam were stretched cables, three in number and eight digits
thick, fastened just as in a ship from stem to stern continuously, and
these cables were bound with cross girdles a foot and a quarter apart.
Over these the whole ram was wrapped with rawhide. The ends of the ropes
from which the ram hung were made of fourfold chains of iron, and these
chains were themselves wrapped in rawhide.
7. Likewise, the projecting end of the ram had a box framed and
constructed of boards, in which was stretched a net made of rather large
ropes, over the rough surfaces of which one easily reached the wall
without the feet slipping. And this machine moved in six directions,
forward (and backward), also to the right or left, and likewise it was
elevated by extending it upwards and depressed by inclining it
downwards. The machine could be elevated to a height sufficient to throw
down a wall of about one hundred feet, and likewise in its thrust it
covered a space from right to left of not less than one hundred feet.
One hundred men controlled it, though it had a weight of four thousand
talents, which is four hundred and eighty thousand pounds.
CHAPTER XVI
MEASURES OF DEFENCE
1. With regard to scorpiones, catapults, and ballistae, likewise with
regard to tortoises and towers, I have set forth, as seemed to me
especially appropriate, both by whom they were invented and in what
manner they should be constructed. But I have not considered it as
necessary to describe ladders, cranes, and other things, the principles
of which are simpler, for the soldiers usually construct these by
themselves, nor can these very machines be useful in all places nor in
the same way, since fortifications differ from each other, and so also
the bravery of nations. For siege works against bold and venturesome men
should be constructed on one plan, on another against cautious men, and
on still another against the cowardly.
2. And so, if any one pays attention to these directions, and by
selection adapts their various principles to a single structure, he will
not be in need of further aids, but will be able, without hesitation, to
design such machines as the circumstances or the situations demand. With
regard to works of defence, it is not necessary to write, since the
enemy do not construct their defences in conformity with our books, but
their contrivances are frequently foiled, on the spur of the moment, by
some shrewd, hastily conceived plan, without the aid of machines, as is
said to have been the experience of the Rhodians.
3. For Diognetus was a Rhodian architect, to whom, as an honour, was
granted out of the public treasury a fixed annual payment commensurate
with the dignity of his art. At this time an architect from Aradus,
Callias by name, coming to Rhodes, gave a public lecture, and showed a
model of a wall, over which he set a machine on a revolving crane with
which he seized an helepolis as it approached the fortifications, and
brought it inside the wall. The Rhodians, when they had seen this model,
filled with admiration, took from Diognetus the yearly grant and
transferred this honour to Callias.
4. Meanwhile, king Demetrius, who because of his stubborn courage was
called Poliorcetes, making war on Rhodes, brought with him a famous
Athenian architect named Epimachus. He constructed at enormous expense,
with the utmost care and exertion, an helepolis one hundred and
thirty-five feet high and sixty feet broad. He strengthened it with hair
and rawhide so that it could withstand the blow of a stone weighing
three hundred and sixty pounds shot from a ballista; the machine itself
weighed three hundred and sixty thousand pounds. When Callias was asked
by the Rhodians to construct a machine to resist this helepolis, and to
bring it within the wall as he had promised, he said that it was
impossible.
5. For not all things are practicable on identical principles, but there
are some things which, when enlarged in imitation of small models, are
effective, others cannot have models, but are constructed independently
of them, while there are some which appear feasible in models, but when
they have begun to increase in size are impracticable, as we can observe
in the following instance. A half inch, inch, or inch and a half hole is
bored with an auger, but if we should wish, in the same manner, to bore
a hole a quarter of a foot in breadth, it is impracticable, while one of
half a foot or more seems not even conceivable.