§ 3  Highly esteemed Marcellus, so far as anyone who writes about machines can generally follow it, I have taken into consideration the Delphic precept, that there is some divine power that reminds us that we should be sparing with time. One might almost say that we always squander it lavishly on the pressing necessities of life. And so, let us not devote any casual attention or concern to money and the other things that seem valuable to us; but rather let us pay attention to the precepts of the ancients. At the expense of only a small degree of effort we shall earn our living in no random way and easily get a share from others. But instead we waste time that is subject to change and flows away since the end comes all too soon.

§ 4  And we do this even though it is nature's way to provide us by day with some faculty for acquiring each of life's necessities, and by night with sleep, though it be altogether brief. For the one man who alone has rightly been called a poet does not allow sleep (the gift of the gods for the relaxation of our bodies) to last all night. In this way he is clearly taking great forethought to prevent the mind from lying idle for a long time.
Those authors who describe some topic or have some instruction to give us, even when they seem to be doing it for our benefit, waste time quite unreasonably in unnecessary words in order to display their great learning.
For they leave behind books filled with digressions, even though the ancient philosophers gave good advice when they said that one should know the measure of life’s opportunity since this is the end of wisdom.

§ 5  In this way, in respect to a treatise on technical matters, a man by carefully applying himself to it, would derive some benefit from that Delphic precept rather than from the writing of Straton, Hestiaios, Archytas, Aristotle, and the others who have written like them. For while, to young men eager for knowledge, their writing would be useful in acquiring basic principles, to those who want to accomplish something immediately it would be completely divorced from an inquiry that leads to results.
Therefore Kalanos the Indian’s remark to them would seem to be right. He says, "We do not compare ourselves to the Greek philosophers who waste many words on inconsequential matters but we are accustomed to say very little about even the gravest matters so that they may be easily remembered by all." One can understand very accurately how great the difference is between the oriental works and the Greek ones from the Persika of Deimachos, from those who followed Alexander, and even more from Pyrrhos of Macedon’s work on siege-machines.

§ 6  But so that I myself may not appear verbose I shall return to the matter in hand adding a few embellishments to satisfy those who are accustomed to examine pedantically the style of expression. For I do not assume that it is suitable for a man working out these refinements to fall behind in his purpose. This is exactly what happened to the orator Isokrates in the case of the letter of advice that he sent to Philip. The war was resolved before he had finished his advice. Therefore he says, "While I was concerned with this business you made peace before I
had finished it." Furthermore, it is my opinion that we should obey those who give good advice in such matters.
For the historian Kallisthenes says that the man who is attempting to write something must not miss the point but must arrange his words to suit both himself and his subject matter. I think that every treatise on a technical subject of this sort requires conciseness and clarity and is not suitable material for the laws of rhetoric.
For this reason I shall go through in detail what I have read in the works of the engineer Agesistratos.
"Therefore it appears to be very necessary to have experience in blueprints. For in this way it is possible for someone devising measures for a siege to devise also the correct countermeasures and conversely to devise measures against the countermeasures. This, however, the common man cannot do easily but only a man who has learned mechanics well, is steeped in all the studies dealing with them, and has carefully considered the works written by earlier men or produced in relation to this matter.

§ 8  For it is often profitable to use the good inventions from the past and not in every case to be an innovator, unless one is intent on deceiving the laymen by preferring the appearance of truth to the truth itself."
This seems to me well said. For in his work Belika, Agesistratos so far surpassed his predecessors that even the man who proclaims his merits is not easily believed. For his catapult of three spans (0.66m) with twelve minas (7.37 Kg.) of torsion gut had a range of three and one-half stades (621.60m) and the four cubit (1.78m) one, which was a palintone, had a range of four stades (710.4m).
Apollonios, who was his teacher, brought such a great cargo of stones for the mound around the harbour of Rhodes that witnesses were often at a loss to know how he ever loaded it into the ships and unloaded it again in Rhodes. After this Agesistratos followed Apollonios striving to find something useful in his treatise on siege-techniques.

§ 9  His "ram-bearing tortoise" and the counter-device illustrate this. Therefore it seemed that the advice such a man gives about mechanics should be trusted.
He said that the very first "ram" was invented by the Carthaginians at the siege of Gades. For when they were seizing a certain outpost in advance and were knocking the walls down to the foundation, some young men, who had no tools for its destruction, took hold of a beam in their arms and beat it against the wall and in this way easily destroyed a great length of it. A certain Tyrian shipbuilder, by the name of Pephrasmenos, witnessed the event. In the siege which they later conducted against the city of Gades he set up a vertical beam and from this he suspended another beam at right angles to it, similar to the beams of a balance, and he began to strike the wall by hauling the horizontal beam by means of a pulley-rope. Since those inside were perplexed owing to the strangeness of the machine, the walls soon fell. After this man, Geras, the Carthaginian, made a frame on wheels and put the "ram" on it sideways.

§ 10  Rather than hauling it with a pulley-rope he arranged for a wheeled cover to be pushed forward by a large number of men. And Geras, who first invented this, called it a "tortoise" on account of its slowness. After this some men arranged for the "ram” to be pushed forward on rollers and used it in the same manner.
The construction of engines of war of this kind improved in general under the tyranny of Dionysios of Sicily and under the reign of Philip the son of Amyntas when he was besieging Byzantium. Polyeidos the Thessalian was successful in the field of mechanics and his pupils, Diades and Charias, campaigned with Alexander. Diades himself says, in his writing on mechanics, that he invented moveable towers, the machine known as the "trypanon," the "crow,” and the scaling-ladder.

§ 11  He also made use of the "ram” mounted on wheels, or at any rate he describes the construction of it as follows. (Construction of a "Ram") He says that the smallest tower must have a height of 60 cubits (26.60m) and a width of 17 cubits (7.55m), the width decreasing by one-fifth towards the top. The thickness of the side poles of the tower should be three palms (0.22m) at the bottom and seven fingers (0.13m) at the top. He constructed a tower of this size with ten stories each of which was surrounded by a gallery.

§ 12  The largest of his towers had a height of 120 cubits (53.25m) and a width of 23 1/2 cubits (l0.41m). The width of this tower also decreased by one-fifth towards the top. The side-poles were a foot square at the base decreasing to 6 fingers (0.11m) at the top. His tower of this size was twenty stories tall and for protection against fire each story was surrounded by a parapet, the width of which was three cubits (1.33m). Let the first story have a height of 7 1/2 cubits (3.33m), the second five (2.22m), and those up to the fifth story the same, the rest were four cubits and two palms (1.93m) in height. But for the smaller tower also the division of floors followed the same proportion. These towers were covered with undressed hides.

§ 13  The construction of the "ram-bearing tortoise" was the same whether it was small or large. The biggest had a width of 30 cubits (13.30m) and a length of 40 cubits (17.80m), and the height, not including the gabled roof that was put on later, was 13 cubits (5.77m). The height of the pediment itself, from the floor to the peak, was 16 cubits (7.12m). The gable rose up above the middle of the roof at least two cubits (0.88m) projecting the roof timber at the side as far as the main beams of the gable in order to make a gallery along the sides. From the middle of the roof he erected a small three story tower and placed a catapult in the top stories and a supply of water in the bottom one. Uprights were arranged around the edge of the actual "tortoise” and it had a parapet.

§ 14  Inside it he placed a battering-ram frame on which he placed the cylinder through which the "ram" was propelled by means of a pulley-rope, thus activating the machine. And it was covered with hides in the same way as the towers.
The "trypanon” has the same "tortoise” and exactly the same construction as the "ram”. On the frame he places a barrel very similar to that found in a euthytone catapult and having a windlass placed across it just as they do. At the other end he fixes two pulleys by means of which the beam placed in the groove is thrust forward.
And on the floor of the groove he places numerous rollers so that the beam may move with ease. And in this manner, by means of the windlass set at the bottom end of the groove, he hurls forward and draws back the beam that

§ 14  15 batters down the wall. The groove is surrounded with skins arranged on a framework of arches with the intention of protecting the beam inside it.
If the work is well outlined the engineer may acquire a good reputation, but if he puts down all the details in a full length work he will achieve very great fame thanks to his writings.
Diades says that the grappling-hook is not worth building. Although at the beginning of his work he stated that he would describe how one should construct the scaling-ladder, he failed to do so. Also no information has been given about the machines that he introduced on the sea. But they are also passed over, although he promised most solemnly that he would discuss them.
But I first wrote a description of the "tortoise for filling up ditches" and then of other machines.
Description of "Tortoise for Filling Ditches

§ 16  Philon the Athenian says that this machine is useful for constructing roads for the approach of machines, for laying out sheds, and for filling up ditches or any other depressions that should be filled in. It is also useful for establishing observation-posts.
It is constructed on a platform 14 cubits (6.22m) square, which has four cross-bars and two longitudinal bars, all ten fingers (0.19m) thick and three palms (0.22m) wide. Let each crosspiece be located at intervals of 2 cubits and a palm (1.60m). Each of the corner compartments contains four axle-blocks, in which the axles of the wheels turn, sheathed with iron plates so that whenever one has to move them forward to build approaches (i,.e. to make a broad and level area in front for fighting) or set up machines in line, the wheels may be drawn out after disengaging the axles.

§ 17  There are four wheels three cubits (1.33m) in diameter, one foot (0.30m) thick, and reinforced with cold-forged plates of iron.
To the frame are fixed two pieces of wood projecting 4':cubits (1.78m) from each side of the frame at each end of their length. Two other pieces of wood, projecting for a length of 8 cubits (3.55m) at the front and 4 cubits (1.78m) at the rear, are attached to these projections. The thickness and breadth of these are the same as for the base.
Jointed into the frame itself on the base are posts seven cubits (3.11m) high and spaced one cubit (0.44m) apart. At the top a surrounding architrave makes all these posts fast. And to this are connected rafters supporting one another and increasing the height by 8 cubits (3.55m), The ridge-pole is fastened on top of these rafters. The rafters are provided at intervals with props and cross-rails and the whole roof is fortified with planking, preferably of palm wood, but if this is not available of some other wood that is as elastic as possible, excepting cedar, pine, and alder, which are both inflammable and easily broken.

§ 18  The planking is then covered over with a thin compact coating of wattles as fresh as possible. On top of these there is a covering made of hides stitched together like mattresses and stuffed preferably with marsh-plants, or so-called sea-weed, or chaff steeped in vinegar. These coverings are effective against both the blows of catapults and fire.
There is another "tortoise for filling in ditches” constructed in the same manner as the preceding one and having the same beams except for the sloping rafters. Instead, surrounding it, above the posts and architraves, it has a breastwork and battlements built of planks and wattles. Above the timberwork there is a covering of strong planks coated with a mixture of clay and hair of sufficient thickness that fire cannot damage it. And this machine is useful not only for filling in ditches but also for purposes of observation. For the soldiers who enter it propel it towards the wall and are thus able to make observations although they are within range of missiles.

§ 19  This "tortoise" could well have eight wheels but the engineer with an eye to suitable routes of approach may well alter such machines as required.
Concerning the "Mining Tortoise"
In all its other particulars the type of "tortoise" used in sapping operations is designed in much the same way as the preceding ones;

§ 20  however, it has a right-angled surface at the front so that when it has reached the wall it can fit exactly against it and the missiles hurled from the walls may not enter it from the side and the miners inside it can work in safety.

§ 21  The "Tortoise of Hegetor"
The length of the base of the "tortoise" invented by Hegetor of Byzantium is 42 cubits (18.20m) and the width 23 (12.4m). The posts joined to the base are four in number. Each one is made out of two pieces of wood

§ 22  They are made of wood joined alternately in width and thickness and are reinforced with plates of cold-forged metal. They turn in axle-blocks. Posts twelve cubits (5.32m) high, 3 palms (0.22m) wide, and ten fingers (0.19m) thick, are set up on the base. Each post is placed 7 palms (0.52m) from the next and architraves 4 palms (0.30m) wide and 3 palms (0.22m) thick are fastened all around above them. Roof-beams are fastened on these architraves raising the height by 8 cubits (3.55m) And above these the ridge-pole, to which all the extremities of the roof-beams are fastened, is placed horizontally so that we have two sloping roofs. Finally the whole machine is boarded over and protected in the same manner as the "tortoises for filling in ditches".
It also has a middle story resting on the uprights so that the battery of machines may be set up on it.

§ 23  Right in the middle of the "tortoise" behind the frame of the battering-ram, two side poles joined together, thirty cubits (13.3m) in height, one cubit (0.44m) thick, and three palms (0.22m) wide, are fastened. Two cross-bars, one at the top and the other in the middle, are fastened through these side poles. And a vertical piece of wood is fastened between the top and the middle cross-bar through their centres. On each side of this vertical bar and the side poles are turned windlasses from which the ropes holding up the "ram" are fastened. And a parapet is also attached to the top of the ram-frame so that those watching the missiles dispatched against the "ram" by the enemy can stand in it in perfect safety.
The total length of the "ram" is 120 cubits (53.25m).

§ 24  At the butt-end it is 2 feet (0.60m) thick and 5 palms (0.37m) wide but towards the point the thickness diminishes to one foot (0.30m) and the width to 3 palms (0.22m). And it has an iron point similar to the protruding beak of a ship. The body is pipe-shaped and from it extend four iron spirals 10 cubits (4.44m) long that are nailed to the "ram". The whole "ram" is undergirded with three ropes eight fingers (0.15m) thick and is grasped around the middle by cubit long (0.44m) chains in three intervals. The binding holding the "ram" in the middle follows the winding on the beam for a distance of 5 palms (0.37m). When it is wrapped up it is surrounded by raw hides. And the ropes that stretch from the windlasses of the ram-frame and hold up the "ram" have their ends bound with fourfold iron chains. And the chains too are surrounded with hides so that they may not be seen.

§ 25  There is also a scaling-ladder made of boards nailed on to the front end of the "ram" and a net woven from thick rope with a mesh of one palm's breadth (0.07m) is fastened to this so that using it one might easily climb on to the wall. The "ram" also has pieces attached to both sides ...

§ 26  The machine admits of six movements: forward, backward, right and left, and up and down. It can clear a wall up to a height of 70 cubits (31.05m) and can sweep sideways for a range of 70 cubits (31.05m). It is managed by 100 men and has a total weight of four thousand talents (147,440 Kg.).

§ 27  Description of Helepolis
The Helepolis was invented by Epimachos the Athenian and brought to the walls of Rhodes by Demetrios when he was besieging the Rhodians. It is constructed as follows. Its height is 90 cubits (40m) and its width 8 cubits (3.55m). It is like a tower in form and can endure the impact of a stone weighing approximately three talents (111 Kg.).
The naval machines that some people call "sambykai" are not worth describing since everyone is well acquainted with them and I think that they differ so much from each other that often it is preferable that they not be built at all rather than that they be built badly.

§ 28  For the men besieging Chios, because they miscalculated and built the "sambykai" higher than the city's towers, caused the death by fire of those who ascended them because they were unable to reach the towers, and because there was absolutely no way to lower the "sambykai"; for otherwise the ships from which they were suspended would have overturned with the centre of gravity of the load being shifted. Therefore, in common with other craftsmen, engineers who intend to make use of siege machines should not be ignorant of optics.
A similar thing happened to Kallistratos, the writer on machines, while he was directing the transportation of stones to the sanctuary at Ephesos. For he did not realize that some things represented in models on a small scale produce an optical illusion since such things cannot be reproduced on a large scale. On the other hand, it is sometimes impossible to make small models of some things but these can only be constructed immediately in life size.

§ 29  In that case, for example, the triangle that had served as his model for the transport of the stones seemed quite good, but the actual loads could not be conveyed in the same way.
For a siege some men have constructed sorts of ladders similar to those erected in the theatres against the proskenia for the actors. However, they have appeared useless. But I have mentioned them owing to the fact that a number of contemporary engineers, who have made models of this strange wonder, are attempting to deceive people.
In his Commentaria, Ktesibios the Askrenos, the Alexandrian engineer, told how, with the use of the following machine, one can climb on to a city wall without using a ladder.
He says that one should build a four-wheeled cart and mount crosswise on this a square piece of wood with round mortises on each end of it fitting into two upright pieces of wood. Around this one places a large tube suspended on a pivot — large enough that a man can easily enter it standing upright and walk to and fro.

§ 30  When this has been done, the tube should be raised at whichever end one wishes. For when one end of the tube touches the ground the other end rises because the tube revolves in the notches of the piece of wood on each of its two sides and is suspended on a pivot. And whenever the four wheeled vehicle has been brought up so that the end of the tube is right against the wall, the man inside should open the door of it and climb onto the wall.

§ 31  Ktesibios apparently did not give the dimensions of the components. This machine is of no great worth but is
designed merely as a contrivance to win admiration for the inventor.... And for this reason I have described it fully.
Concerning the construction of tunnels for undermining walls and of protective sheds and the manner of dealing with them, although Pyrrhos, in his work Poliorketika, has described how to build them, I did not think it proper to contradict his excellent account; which is what I see most people doing in their writing.
In composing an accurate discussion on each machine I have very carefully considered everything that my predecessors gave a good description of. And besides, I have prided myself in the fact that I have contributed additional Information for the construction of engines of war.

§ 32  For one ought not only to be acquainted with the clever inventions of others, but also, since he is still enthusiastic, to invent something oneself, For some engineers, whenever they propose to capture a city on the sea, are wont to strap the machines on freighters and in calm weather to push them up to the walls. But if they are caught by the wind and the waves swell and break over the hulls, the machine, supported by them rolls about because the hulls do not share the same movement. Then, as the machines break up because of the self-destructive character of their design, the enemy take heart. Therefore it is necessary to fit the so-called πιθήκιον into the middle of the platform that rests upon the ships so that, in spite of the surging of the waves, the machine may remain upright in any weather.

§ 33  For protection against the winds it is also necessary to have a windscreen and to limit helepoleis to small dimensions. Whenever the ships approach the walls the machines are set up on them by means of compound pulleys. Here is the Boat

§ 34  It also seems a good idea to me to furnish a fore-wheel for every "tortoise" and siege-engine so that its progress may follow a crooked course. This ensures that the rock-throwers may not hit their mark. The so-called θερμαστρίς is constructed in the middle of the front of the base and projects forward three cubits (1.33m). It is fitted with a μασχάλην bound together with cold-forged metal, into which the rudder is inserted. The spherical fore-wheel is then attached to the rudder.

§ 35  A plaited rope 16 fingers (0.30m) thick is put through the rudder and its ends are attached on the inside around the axle so that as the axle turns the machine moves in the desired direction.
I think that the "chamber" is also a good idea. It will be placed on the "ram-bearing tortoise", the side pieces of which will be ash wood bound with cold-forged metal plates so that they may be inserted into a metal axle.

§ 36  Each one of them will weigh one talent (36.86 Kg,). And the iron axle, which weighs four talents (147.5 Kg.), is inserted into them. The machine called a "crane" is fixed into this in such a way that so far as one can estimate by eye it reaches the top of the besieged walls.
Above this are to be nailed vaulted tubes, inside of which a wicker mat will be fitted. At the top end a folding ladder with iron hooks underneath is fastened so that whenever the machine presses against the city battlements, the ladder-apparatus may be brought into use by means of ropes and the hooks may firmly grab hold of the battlements. The "crane” is undergirded and covered with skins in the same manner as the "ram" already discussed.

§ 37  A counter-weight of one thousand talents (36,860 Kg.) is placed at the rear end. The axles, however, operate just as efficiently by means of the screw. This machine can also move in six directions. Here is the "Chamber"
In difficult and rough terrain the machine should not be brought forward. For in these circumstances the enemy are especially troublesome, throwing headlong from the battlements immense rocks, large stone drums, and other similar objects. These missiles, borne along by their own impetus, produce an irresistible force.

§ 38  In such circumstances, then, one must counteract their impetus with the following device. Triple spikes 5 cubits (2.22m) long and as thick as a girdle must be set up in sufficient number that we may surround the place out of missile range. And since the triple spikes are pushed forward as a result of the daily rush of stones the spikes should be placed three or even four deep. The reason for this arrangement of the spikes is to ensure that the missiles rolling down will always hit them because they have to pass through several ranks of them.
When the besiegers wish to be nearer to the wall they bring up the "areté tortoise" and using this will set up ladders. The "areté tortoise" is wedge-shaped and has a perfectly round roof above in the shape of a hemispherical dome so that anything that falls on its roof readily rolls off it.

§ 39  But do not imagine that I am so harsh as to bring together all these notes for the destruction of cities, when, in fact, the opposite is the case. The treatise that I have just compiled makes cities safe, for those who are acquainted with these devices will easily be able to guard against the very things that are liable to harm them. I have written this especially against those who refuse to obey the fine laws of the realm (hegemonias). Therefore, if you approve, all the machines will be illustrated with figures and what is difficult to explain in words will thus become obvious.
With regard to what contrivances one should make to counteract those described above, when I find any details in the works of older writers, I shall attempt to describe them also to you.

§ 40  This is said because some people measure the misery of their neighbours by their own sloth and claim that a knowledge of practical affairs cannot be acquired even over a long period of time, just as if scientific knowledge were bound to have a dulling effect on our enthusiasm.