An Ancient Greek Machine Gun? The Innovative Catapult of Dionysius

An Ancient Greek Machine Gun? The Innovative Catapult of Dionysius

The polybolos (which may be translated literally as ‘multiple thrower’) was a type of weapon used in the ancient world. That’s why it’s sometimes referred to as an ancient machine gun.

Polybolos: Improving on the Catapult

Whilst the catapult was likely to have been used since the 9th century BC (based on a relief from Nimrud), it was during the 4th century BC that the catapult began gaining popularity throughout the Mediterranean. In the Greek world, early catapults were large bows that relied on winches to draw the weapon back for firing. It may have been during the time of Philip II of Macedon (the father of Alexander the Great) that tight bundles of sinew / rope that functioned as ‘springs’ were used to replace the bow arms of the catapult. These catapults relied on torsion to fire their projectiles, and could either be used to fire arrows, like their predecessors, or be modified so that heavier projectiles, such as stones, could be hurled at enemy defences.

Engraving of thirteenth-century catapult for throwing Greek fire. ( Public Domain )

The polybolos was a further improvement on the catapult technology that existed at that point of time. The polybolos is commonly believed to have been invented during the 3rd century BC by Dionysius of Alexandria, a Greek engineer who was working at the arsenal of Rhodes. During that time, the Rhodians had a particular interest in artillery, and were keeping abreast with the latest developments in this aspect of warfare. This was aided by their close relation with Ptolemaic Alexandria. It was at Rhodes that Philo of Byzantium, a Greek engineer and writer on mechanics, encountered and inspected a catapult made by Dionysius of Alexandria. This is recorded in Philo’s Belopoeica (a treatise on artillery), and our knowledge of the polybolos is derived from this piece of writing.

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An automatic catapult, perhaps what a polybolos could have looked like. (SBA73/ CC BY SA 3.0 )

Features of the Polybolos Catapult

Unlike the standard catapults / ballistae of the day, the polybolos could fire multiple projectiles before it needed to be reloaded. There were flat-linked chains on each side of the polybolos, which ran over pentagonal prisms at each end of the chain’s loop. It has been speculated that these prisms worked as inverted gears. By having a soldier turn the windlass attached to the rear prism, bolts could be locked, loaded and fired automatically. These projectiles were fed into the polybolos via a magazine that was attached to a rotating tray. This gave the polybolos a higher rate of fire than other ancient artillery pieces. For instance, a modern reconstruction of this weapon was found to have a firing rate of at least three times that of a standard scorpion (another artillery piece used by the Roman army).

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Parts of a polybolos. ( Hellenica World )

Using the Polybolos Catapult to Attack

The polybolos was used mainly against enemy personnel, rather than against defensive structures such as walls or towers. One of the reasons contributing to this is the fact that the polybolos was able to lock on to a target. This, however, may also be a disadvantage of the weapon. An ancient writer is recorded to have complained that the polybolos was too accurate. The lack of dispersion in the shot pattern meant that using this piece of equipment to kill human units was an overkill.

A 19th century reconstruction of a polybolos by a German engineer by the name of Erwin Schramm, for example, was reported to have been so accurate that the second bolt fired from the weapon was able to hit its target, and in the process, split the first bolt.

Schramm’s reconstruction of a polybolos, in the Saalburg, Germany. ( CC BY SA 2.0 )


    Polybolos

    Polybolos was an ancient Greek repeating ballista reputedly invented by Dionysius of Alexandria, a 3rd-century BC Greek engineer at the Rhodes arsenal Ώ] ΐ] and used in antiquity. Philo of Byzantium encountered and described the polybolos, a catapult that like a modern machine gun could fire again and again without a need to reload. Α] Philo left a detailed description of the gears that powered its chain drive, the oldest known application of such a mechanism, Ώ] and that placed bolt after bolt into its firing slot.


    Ancient Greek Artillery Technology from Catapults to the Architronio Canon

    Archimedes,” said Lucius, “we know that without your war machinery Syracuse wouldn’t have held out for a month as it is, we’ve had a rough two years because of them. Don’t think we soldiers don’t appreciate that. They’re superb machines. My congratulations.”
    Archimedes waved his hand. “Please, they’re nothing really. Ordinary hurling mechanisms—mere toys, that’s all. Scientifically, they have little value. Karel Capek , Apocryphal Tales

    Bows (the first machine invented by man?) were used at least since 8000 BC according to cave paintings in 'les Dogues' (Castellón, France). Probably bows were invented much earlier (around 20000 BC). The word Catapult comes from the Greek words kata and peltes. (Kata means downward and peltes describes a small shield ). Catapult means therefore shield piercer. Catapults were first invented about 400 BC in the Greek town Syracus under Dionysios I (c. 432-367 BC). The Greek engineers first constructed a comparatively small machine, the gastraphetes (belly-bow), a version of a crossbow. The gastraphetes is a large bow mounted on a case, one end of which rested on the belly of the person using it. When the demands of war required a faster, stronger weapon, the device was enlarged, and a winch pull-back system and base were added.

    Technology of Catapults (belopoietic from belos (arrow or it is better to say a bolt) and poiw make) was a key part of ancient mechanics, a branch of mathematics that also included fortification building, statics, and pneumatics.

    Many, though, have begun the construction of weapons of the same size, and have made use of the same system of rules, the same types of wood, and the same amounts of iron, and have kept to the same weight, yet of these some have made machines that throw their missiles far and with great force, while those made by others have lagged behind their specifications. When asked why this happened, the latter have been at a loss for an answer. So it is appropriate to warn the prospective engineer of the saying of Polykleitos the sculptor: perfection, he said, comes about little by little [para mikron] through many numbers. And in the same way, as far as concerns our science, it happens that in many of the items that go to make up the machine a tiny deviation is made each time, resulting in a large cumulative error. Philo Mechanicu s

    Later, weapons fired by torsion bars powered by horsehair and ox tendon (the Greeks called this material neuron ) springs could fire arrows, stones, and pots of burning pitch along a parabolic arc. Some of these machines were quite large and heavy and this were thus mounted on wheels to improve tactical mobility and deployment. The production method is not known.

    Interesting is also this information:

    When horse-hair and other materials failed, the women in several instances cut off their own hair and twisted it into ropes for the engines (Caes. BC iii.9 Veget. De Re Mil. iv.9). William Smith, D.C.L., LL.D.: A Dictionary of Greek and Roman Antiquities, John Murray, London, 1875.”

    A palintonon or palintone translates as "V-spring" and euthytonon or euthytone (Ευθύτονος) translates as "straight-spring" from Greek. The "V" or straight spring refers to how siege engines are compared to shape of hand-held bows when it comes to how the arms are shaped.

    Stones. (lithobolos (Λιθοβόλος) i.e. stone thrower )

    Other. “When a rampart composed of the trunks of trees is raised opposite to a wall, it may be consumed by discharging red hot iron bars against it from the balistae. “ Marcus Vitruvius Pollio : de Architectura

    Flexion based Artillery

    The Gastraphetes ( γαστραφέτης ), a form of primitive crossbow that fired a wooden bolt on a flat trajectory along a slot in the aiming rod. Main components (syrinx / pipe and diostra / slider). Could reach a bow length of 15 feet and could fire a stone of 40 pounds some 200 to 300 yards. Mainly known from Heron of Alexandria references. It was used successfully during the siege of Motya, a Carthaginian island fortress on the west end of Sicily, in 397 BC and Greek engineers improved further the capabilities of the device reaching its physical limitations. The army of Dionysius I surprised the Carthaginias with the newly developed gastraphetes with its larger range. The desciption of Heron of Alexandria is based on an older by Ctesibius.


    Oxybeles ( Οξυβόλος ) (Greek word that means bolt shooter)


    Zopyrus's gastraphetes from Zopyrus a specialist in gastraphetes design from Tarentum Southern Italy. A step towards the torsion catapult, including a stand for the heavy gastraphetes version.


    The stone thrower of Charon of Magnesia

    Biton addressed his artillery treatise to king Attalus I of Pergamum (241 to 197 B.C.),

    The Roman army had stone-throwers capable of hurling projectiles weighing 27 kg across a distance of 150 meters. Archimedes' legendary engines are said to have used stones three times as heavy. Plutarch tells us that it was Hiero, another king of Syracuse, who spurred Archimedes into military engineering. His splendid catapults kept the Roman troops at bay until the besieged city fell in 212 B.C. as a result of treachery.

    The engineers saw themselves as an international community: Philo mentions his exchanges with colleagues in Alexandria and Rhodes, Biton his colleagues from Magnesia, Abydos, Macedonia, and Colophon. They also traveled: for instance, Zopyrus, a specialist in belly-bow design from Tarentum in Southern Italy, created one design in Miletus (Asia Minor) and another in Cumae (central Italy)

    Torsion based Artillery

    The principle of torsion was probably discovered by artificers working in Macedonia under Philip II and Polyidus between 353 and 341 BC. There exists no hint of torsion catapults before Philip's reign. Ath the siege of Perinthus and Byzantium (340 BC) Philip deployed torsion arrow-shooting catapults. Marsden, Invention of the catapult

    Torsion catapults probably around 340 BC. Inscriptions from the Chalkothek on the Acropolis of Athens mentions torsion spring catapults at about 330 BC. Oxybeles could pierce a shield and armor of warrior in 400 meter distance.

    It was Philip of Macedon who first organized a special group of artillery engineers within his army to design and build catapults. Philip's use of siegecraft allowed Greek science and engineering an opportunity to contribute to the art of war, and by the time of Demetrios I (305 B.C.), known more commonly by his nickname "Poliorcetes" (the Besieger), Greek inventiveness in military engineering was probably the best in the ancient world.

    Alexander the Great used catapults in a completely different way -- as covering artillery. Alexander's army carried prefabricated catapults that weighed only 85 pounds. Larger machines were dismantled and carried along in wagons. Alexander's engineers contributed a number of new ideas. Major Greek cities adopted the use of catapults and owned a park of torsion artillery.

    Philo of Byzantium refers casually (Pol. 91. 36) to one-armed stone-throwing machines (later Roman versions also called onager)


    Euthyntonon, Torsion weapon

    Palintonon (or Ballista in Roman)

    Heavy Artillery Weapon up to 3 tons weight (Transport in pieces). 13 kg stone (Two lever) Around 335 BC.

    Spherical stones (10-80 pounds)


    Palintonon. Plans from "Build Your Own Greek Siege Engine" by Kurt Suleski

    Cheiroballista (Two lever)

    Introduction of metal frames.

    The Cheiroballistra (called Manuballista by the Romans), a device that hurls arrows over a large distance. Some say that it was actually written around 100 AD (after Heron). As an inventor Apollodorus of Damascus is proposed working for the Roman army.

    In this particular engine, the springs are stretched in two separate metal casings. A metal stud was attached the top of each of the field frames, to hold them together. Another stud was attached to the bottom of the field frames and the base of the engine, to hold the spring casings in place (Marsden 209). Heron's cheiroballistra represents the most advanced two-armed torsion engine used by the Roman army.

    The repeating Catapult developed in the 3 rd century BC was too complicated to be used widely.

    Only few metallic parts of catapults survived and projectiles (stones, bolts).

    Engineers at Rhodes were known to have produced a palintonon that could shot stones and also arrows

    The use of catapults in the field is evidenced in one of Alexander's early battles in the Northern Marches of Macedon. At Pelion, Alexander, in a rare loss of the initiative had to extract his army from a siege position around the town and cross a river to a defensive position in the foothills. Surrounded, Alexander lulled the barbarian army into watching his phalanx and cavalry maneuver on the plain outside of the city, then in a typical lightening move, he forced a crossing of the river creating a defensive bridgehead. He then set up some of his siege artillery to fire back across the river, over the heads of his own troops to cover their rear with a curtain of missiles as they crossed the river after disengaging with the enemy. This is the first reported use of siege artillery in the field as an assault weapon (in spite of the fact that it was used defensively). Alexander the Great and His Army

    In 334 BC Alexander the Great used at the siege of Halicarnassus heavy palintona. At Tyre he used arrow catapults and palintona against the wall fortifications. http://www.perseus.tufts.edu/cgi-bin/ptext?doc=Perseus%3Atext%3A1999.04.0009&layout=&loc=16.10.html

    At the siege of Gaza in 332 BC. Alexander was wounded in the neck by a catapult arrow that had pierced both his shield and his breastplate.

    Philo of Byzantium, in an artillery manual written in about 200 B.C., stated that a wall had to be at least 4.62 meters thick to withstand catapult stones and that it was a good idea to keep the stone throwers at least 150 meters distant by means of ditches and other obstacles.

    The palintonon could fire a stone over a range greater than that of a Napoleonic cannon.

    It is interesting to note that the largest stone-thrower on record, a three-talent (78 kilogram) machine, was built by Archimedes.

    In honor of the Greek contributions, to this day the military art of siege warfare is called poliorcetics.

    The main catapult significance according to O'Connell is that it: embodied the deliberate exploration of physical and mechanical principles to improve armaments.

    The Syracusia probably the largest transport ship designed by Archias of Corinth around 240 BC with the help of Archimedes had eight deck towers including a 18-foot arrow or 180 pound stone catapult build by Archimedes (One if not the largest catapults used on a ship?). Crew that use the Catapults: Katapeltaphetai (Catapultists) equivalent of today naval gunners. Demetrius's Poliorcetes probably used for the first time catapults on his large warships against the fleet of Ptolemy I at Salamis in Cyprus in 306 BC (His catapults could even use 78 kg stones as projectiles (superheavy category), although a wide range of stone balls have been found , with around 3kg as light category)

    The Romans inherited the Catapult Technology from the Greeks and developed new types such as the onager. As many as 10 Catapults and 60 Ballistae were assigned to each legion.

    The Steam Canon of Archimedes

    Archimedes Canon, Leonardo Da Vinci:

    The catapult development started in Sicily with the Greek tyrant Dionysios I providing the financial means required for the experiments that were necessary to find the optimal design. Except in Sicily , Rhodes and Alexandria were the main centers of the development of the catapult technology, in Alexandria advanced by the support of the Greek Ptolemaic kings of Egypt. In the end of the first century AD the Roman engineer Sextus Frontinus wrote in Strategemeta that the war devices have reached their [physical] limits a long time ago and there is no hope for improvements.

    There were unique devices produced by Archimedes such as a catapult that used steam power and in principle was a canon. It was described by Cicero in a manuscript discovered in a church library by Francisco Petrarch (1304 -1374) . Petrarch collected Greek and Roman manuscripts neglected in various libraries for many centuries: His remark: "

    "Each famous author of antiquity whom I recover places a new offence and another cause of dishonor to the charge of earlier generations, who, not satisfied with their own disgraceful barrenness, permitted the fruit of other minds, and the writings that their ancestors had produced by toil and application, to perish through insufferable neglect. Although they had nothing of their own to hand down to those who were to come after, they robbed posterity of its ancestral heritage"

    Leonardo's quotations from books and his lists of titles supply nothing more than a hint as to his occasional literary studies or recreations. It was evidently no part of his ambition to be deeply read and he more than once expressly states that he did not recognise the authority of the Ancients, on scientific questions, which in his day was held paramount. Archimedes is the sole exception, and Leonardo frankly owns his admiration for the illustrious Greek to whose genius his own was so much akin. The Notebooks of Leonardo Da Vinci

    Architronito e una macchina di fino rame, invenzlon d' Archimede. Leonardo Da Vinci:

    The Cicero manuscript later was used by Leonardo Da Vinci who called the device "Architronito" in honour of Archimedes. He produced only drawings of the steam gun but Ioannis Sakas, a Greek expert of the work of Archimedes used this information to build a test device in 12.5.1981. A vessel was heated and when it reached 400 degrees Celsius 6 g of water was enough to produce in 10 seconds steam that expanding could throw a tennis ball size stone 50 meters. The reconstructed Archimedes steam gun by Sakas was only 1/5 the size of the original.

    A Greek newspaper reported 3 days later about the result of the experiment of Sakas. From another Greek website the numbers which are given for the original is that it was able to shoot a 23 kg stone in 1100 meters and it was invented by Archimedes probably around 213 BC one year before his death. The Greek expert Evangelos Stamatis provided even a better performance estimate: 1.2 km for a 36 kg object. As Cicero reports Archimedes experimented with various devices to be used against the Romans (See for example the burning Mirrors). If and how the device was used by the Greek Syracuseans in practice and why such a device was not used or developed further by the Romans is unknown.

    Famous Catapult Engineers or Authors

    • Polydias, Diades of Pella and Charias (working for Philip and Alexander the Great).
    • Diades helped Alexander at the sieges of Halicarnassus (334 BC) and Gaza (332 BC). He constructed various siege engines.
    • Zopyrus of Tarentum ( Ζώπυρος ο Ταραντίνος ), Charon of Magnesia ( Χάρων ο Μαγνήσιος ), Philon of Byzantium ( Φίλων ο Βυζάντιος ), Biton ( Βίτων ), Ctesibius of Alexandria ( Κτησίβιος ο Αλεξανδρεύς ), Archimedes of Syracuse ( Αρχιμήδης o Συρακούσιος ), Dionysius of Alexandria ( Διονύσιος ο Αλεξανδρεύς ), Hero of Alexandria ( Ηρων ο Αλεξανδρεύς ), Vitruvius.

    (Heron, Philon, Biton and Vitruvius are the main sources of information about ancient Catapults)

    Philon of Byzantium c. (280-220) BC

    Mechanics treatise "Mechanike syntaxis" (9 books) (250 BC)
    1. Introduction
    2. On the lever
    3. On the building of seaports
    4. On catapults *
    5. On pneumatics *
    6. On automatic theatres
    7. On the building of fortresses *
    8. On besieging and defending towns *

    9. On stratagems

    The word "Bombarde" comes from the Greek bombos i.e. bee meaning a loud humming sound.
    The word ballistic comes from the Greek ba'llein, "throw"

    Movement tends to create fire in wood, stone, and iron and with even more reason should it have that effect on air, a substance which is closer to fire than these. An example is that of missiles, which as they move are themselves fired so strongly that leaden balls are melted and if they are fired the surrounding air must be similarly affected. Aristotle , On the Heavens Book II Chapter 7


    Polybolos - an ancient Greek repeating ballista


    Polybolos was an ancient Greek repeating ballista reputedly invented by Dionysius of Alexandria, a 3rd century BC Greek engineer at the Rhodes arsenal and used in antiquity. Philo of Byzantium encountered and described the polybolos, a catapult that like a modern machine gun could fire again and again without a need to reload. Philo left a detailed description of the gears that powered its chain drive, the oldest known application of such a mechanism, and that placed bolt after bolt into its firing slot. No archeological evidence has yet been found that would authenticate later accounts of its use.

    The polybolos would have differed from an ordinary ballista in that it had a wooden magazine over the mensa (the cradle that holds the bolt prior to firing) capable of holding several dozen bolts. The mechanism is unique in that it is driven by a flat-link chain connected to a windlass the flat-link chain is an invention more often attributed to Leonardo da Vinci.

    When loading a new bolt, the windlass is rotated counter-clockwise with the trigger claw raised this drives the mensa forward towards the bow string, where a metal lug pushes the trigger under the trigger claw, which is closed over the string.

    Once the string is locked into the trigger mechanism, the windlass is then rotated clockwise, drawing the mensa back, drawing the bow string with it.

    A round wooden pole in the bottom of the magazine is rotated down toward the mensa as it is drawn to the back of the polybolos, dropping a single bolt into the tray, ready to be fired. As the mensa is pulled farther back, it meets another lug like the one that locked the string into position, this one pushes the trigger and automatically fires the polybolos, and the process is repeated. The repetition provides the weapon's name, in Greek "πολυβόλος", "throwing many missiles", from "πολύς" (polys), "multiple, many" and -βόλος - -bolos "thrower", in turn from "βάλλω" (ballo), "to throw, to hurl", literally a repeating weapon.

    In 2010 a reconstruction was built by the crew of MythBusters, who concluded that it was a plausible weapon.


    Contents

    Ancient Assyria through the Roman Empire Edit

    The earliest siege engines appear to be simple movable roofed towers used for cover to advance to the defenders' walls in conjunction with scaling ladders, depicted during the Middle Kingdom of Egypt. [2] Advanced siege engines including battering rams were used by Assyrians, followed by the catapult in ancient Greece. In Kush siege towers as well as battering rams were built from the 8th century and employed in Kushite siege warfare, such as the siege of Ashmunein in 715 BC. [3] [4] The Spartans used battering rams in the Siege of Plataea in 429 BC, but it seems that the Greeks limited their use of siege engines to assault ladders, though Peloponnesian forces used something resembling flamethrowers.

    The first Mediterranean people to use advanced siege machinery were the Carthaginians, who used siege towers and battering rams against the Greek colonies of Sicily. These engines influenced the ruler of Syracuse, Dionysius I, who developed a catapult in 399 BC. [5]

    The first two rulers to make use of siege engines to a large extent were Philip II of Macedonia and Alexander the Great. Their large engines spurred an evolution that led to impressive machines, like the Demetrius Poliorcetes' Helepolis (or "Taker of Cities") of 304 BC: nine stories high and plated with iron, it stood 40 m (130 ft) tall and 21 m (69 ft) wide, weighing 180 t (400,000 lb). The most used engines were simple battering rams, or tortoises, propelled in several ingenious ways that allowed the attackers to reach the walls or ditches with a certain degree of safety. For sea sieges or battles, seesaw-like machines (sambykē or sambuca) were used. These were giant ladders, hinged and mounted on a base mechanism and used for transferring marines onto the sea walls of coastal towns. They were normally mounted on two or more ships tied together and some sambykē included shields at the top to protect the climbers from arrows. Other hinged engines were used to catch enemy equipment or even opposing soldiers with opposable appendices which are probably ancestors to the Roman corvus. Other weapons dropped heavy weights on opposing soldiers. [ citation needed ]

    The Romans preferred to assault enemy walls by building earthen ramps (agger) or simply scaling the walls, as in the early siege of the Samnite city of Silvium (306 BC). Soldiers working at the ramps were protected by shelters called vineae, that were arranged to form a long corridor. Convex wicker shields were used to form a screen (plutei or plute in English) [6] to protect the front of the corridor during construction of the ramp. [7] Another Roman siege engine sometimes used resembled the Greek ditch-filling tortoise, [ clarification needed ] called a musculus ("muscle"). Battering rams were also widespread. The Roman Legions first used siege towers around 200 BC in the first century BC, Julius Caesar accomplished a siege at Uxellodunum in Gaul using a ten-story siege tower. [7] Romans were nearly always successful in besieging a city or fort, due to their persistence, the strength of their forces, their tactics, and their siege engines. [7]

    The first documented occurrence of ancient siege artillery pieces in Europe was the gastraphetes ("belly-bow"), a kind of large crossbow. These were mounted on wooden frames. Greater machines forced the introduction of pulley system for loading the projectiles, which had extended to include stones also. Later torsion siege engines appeared, based on sinew springs. The onager was the main Roman invention in the field.

    Ancient China Edit

    The earliest documented occurrence of ancient siege-artillery pieces in China was the levered principled traction catapult and an 8 ft (2.4 m) high siege crossbow from the Mozi (Mo Jing), a Mohist text written at about the 4th – 3rd century BC by followers of Mozi who founded the Mohist school of thought during the late Spring and Autumn period and the early Warring States period. Much of what we now know of the siege technology of the time comes from Books 14 and 15 (Chapters 52 to 71) on Siege Warfare from the Mo Jing. Recorded and preserved on bamboo strips, much of the text is now extremely corrupted. However, despite the heavy fragmentation, Mohist diligence and attention to details which set Mo Jing apart from other works ensured that the highly descriptive details of the workings of mechanical devices like Cloud Ladders, Rotating Arcuballistas and Levered Catapults, records of siege techniques and usage of siege weaponry can still be found today. [8]

    Medieval designs include a large number of catapults such as the mangonel, onager, the ballista, the traction trebuchet (first designed in China in the 3rd century BC and brought over to Europe in the 4th century AD), and the counterweight trebuchet (first described by Mardi bin Ali al-Tarsusi in the 12th century, though of unknown origin). These machines used mechanical energy to fling large projectiles to batter down stone walls. Also used were the battering ram and the siege tower, a wooden tower on wheels that allowed attackers to climb up and over castle walls, while protected somewhat from enemy arrows.

    A typical military confrontation in medieval times was for one side to lay siege to an opponent's castle. When properly defended, they had the choice whether to assault the castle directly or to starve the people out by blocking food deliveries, or to employ war machines specifically designed to destroy or circumvent castle defenses. Defending soldiers also used trebuchets and catapults as a defensive advantage.

    Other tactics included setting fires against castle walls in an effort to decompose the cement that held together the individual stones so they could be readily knocked over. Another indirect means was the practice of mining, whereby tunnels were dug under the walls to weaken the foundations and destroy them. A third tactic was the catapulting of diseased animals or human corpses over the walls in order to promote disease which would force the defenders to surrender, an early form of biological warfare.

    With the advent of gunpowder, firearms such as the arquebus and cannon—eventually the petard, mortar and artillery—were developed. These weapons proved so effective that fortifications, such as city walls, had to be low and thick, as exemplified by the designs of Vauban.

    The development of specialized siege artillery, as distinct from field artillery, culminated during World War I and World War II. During the First World War, huge siege guns such as Big Bertha were designed to see use against the modern fortresses of the day. The apex of siege artillery was reached with the German Schwerer Gustav gun, a huge 800 mm (31 in) caliber railway gun, built during early World War II. Schwerer Gustav was initially intended to be used for breaching the French Maginot Line of fortifications, but was not finished in time and (as a sign of the times) the Maginot Line was circumvented by rapid mechanized forces instead of breached in a head-on assault. The long time it took to deploy and move the modern siege guns made them vulnerable to air attack and it also made them unsuited to the rapid troop movements of modern warfare.


    Ctesibius’ Catapult and The Repeating Catapult

    With the domination of the catapult now solidified in the social and pollical hierarchies of ancient civilizations, efforts to further improve the catapult were attempted. Beginning with Ctesibius of Alexandria in mid-3 rd century B.C., this ancient engineer was credited with an attempt to use airtight cylinders and compress bronze springs to pivot rigid firing arms to a point of optimized tension. However, with the compression of air and the introduction of piston friction, unexpected fire and smoke emitted from the catapult’s cylinder were responsible for decreasing both the structural rigidity, as the carpenter’s glue used to construct the device was heated, and range of Ctesibius’ catapult.

    Furthermore, simultaneous development also begun on what is referred to as the “Repeating Catapult” by Dionysius of Alexandria in an arsenal in Rhodes. The repeating catapult, an invention which employed mechanisms not reintroduced until the Renaissance, was a theoretically and idealized model with the intention to automatically fire arrows until a revolving drum containing ammunition was emptied. Essentially proposing a model for an ancient machine gun, this catapult was most notable for its inclusion of a flat-linked chain drive system which was to be later popularized and accredited to Leonardo da Vinci during the early 1500s. This flat-link chain drive, resembling that used on a modern bicycle chain, was to run over a five-sided prism and repeatedly turn a winch to release and draw the main stock of the weapon. Regarding da Vinci’s later involvement with the chain-drive device, this chain drive mechanism precisely embodies what he idolized as the fundamental relationship between an object’s mass and velocity while investigating the basic laws of perpetual motion. Ultimately, this design was never developed due to its paradoxical ability to only fire concentrated shots at a minuscule range of 200 meters that could not be dispersed away from one central target before running out of ammunition.


    Contents

    The early ballistae in Ancient Greece were developed from two weapons called oxybeles and gastraphetes. The gastraphetes ('belly-bow') was a handheld crossbow. It had a composite prod and was spanned by bracing the front end of the weapon against the ground while placing the end of a slider mechanism against the stomach. The operator would then walk forward to arm the weapon while a ratchet prevented it from shooting during loading. This produced a weapon which, it was claimed, could be operated by a person of average strength but which had a power that allowed it to be successfully used against armoured troops. The oxybeles was a bigger and heavier construction employing a winch, and was mounted on a tripod. It had a lower rate of fire and was used as a siege engine.

    With the invention of torsion spring bundle technology, the first ballistae were built. The advantage of this new technology was the fast relaxation time of this system. Thus it was possible to shoot lighter projectiles with higher velocities over a longer distance. By contrast, the comparatively slow relaxation time of a tension machine such as the oxybeles meant that much less energy could be transferred to light projectiles, limiting the effective range of the weapon.

    The earliest form of the ballista is thought to have been developed for Dionysius of Syracuse, c. 400 BC.

    The Greek ballista was a siege weapon. All components that were not made of wood were transported in the baggage train. It would be assembled with local wood, if necessary. Some were positioned inside large, armoured, mobile siege towers or even on the edge of a battlefield. For all of the tactical advantages offered, it was only under Philip II of Macedon, and even more so under his son Alexander, that the ballista began to develop and gain recognition as both a siege engine and field artillery. Historical accounts, for instance, cited that Philip II employed a group of engineers within his army to design and build catapults for his military campaigns. [4] [5] There is even a claim that it was Philip II - with his team of engineers - who invented the ballista after improving Dionysius's device, which was merely an oversized slingshot. [6] It was further perfected by Alexander, whose own team of engineers introduced innovations such as the idea of using springs made from tightly strung coils of rope instead of a bow to achieve more energy and power when throwing projectiles. [6] Polybius reported about the usage of smaller, more portable ballistae, called scorpions, during the Second Punic War.

    Ballistae could be easily modified to shoot both spherical and shaft projectiles, allowing their crews to adapt easily to prevailing battlefield situations in real time.

    As the role of battlefield artillery became more sophisticated, a universal joint (which was invented just for this function) was integrated into the ballista's stand, allowing the operators to alter the trajectory and firing direction of the ballista as required without a lengthy disassembly of the machine.


    Οδοντωτοί Τροχοί , Αρχιμήδης ο Συρακούσιος, Ήρων και Διονύσιος ο Αλεξανδρεύς

    Aristotle mentions gears around 330 BC, (wheel drives in windlasses). He said that the direction of rotation is reversed when one gear wheel drives another gear wheel. Philon of Byzantium was one of the first who used gears in water raising devices. Archimedes used gears in various constructions. Actually we have only indirect knowledge of his inventions. He did not publish any work describing his inventions. He viewed his mechanical inventions as amusements or as practical concerns of no scientific importance. Plutarch says: ''Although these inventions made his superhuman wisdom famous, he nonetheless wrote nothing on these matters because he felt that the construction of all machines and all devices for practical use in general was a low and ignoble business. He himself strove only to remove himself, by his handsomeness and perfection, far from the kingdom of necessity."

    Column drums of a Greek Temple, almost looking like Gears (Olympia Zeus Temple)

    Archimedes is considered to have used gears for:

    A clock that each hour releases a small metallic sphere that falling inside a container produces a sound marking the start of a new hour.


    An odometer. Again a small metallic sphere is released after a specific distance. The number of these small spheres is counted and the distance is thus determined (or the distance can directly be read from a scale).


    A reconstruction of the odometer developed by Archimedes.

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    A drawing of the gears used in Archimedes odometer.

    The Antikythera device which some consider to be developed by Archimedes at least indirect as Archimedes is known to have build so-called planetaria, devices that model the movement of planets and the sun. Two such devices were said to have been rescued from Syracuse when it fell in 212 BC. Also these devices used gears.


    Gears in the Antikythera device


    A reconstruction of the Antikythera device

    Gears were used by others also:

    Dionysius of Alexandria

    A “inverted” version of gears was used by Dionysius of Alexandria in his repeating automatically firing catapult device that fired many arrows like a machine gun.

    The polybolos with its two pentagonal gears linked by a chain drive powered by a windlass.

    Most complex catapult invented in ancient times was a repeating weapon designed by Dionysius of Alexandria, who worked in the arsenal at Rhodes. As this detail drawing shows, arrows were fed by gravity from a magazine into the arrow trough by means of a revolving drum that was slotted to accept one shaft at a time. The revolution of the drum was controlled by a curved cam groove on its surface, which engaged a metal finger mounted on the slider. The motion of the slider was in turn produced by two flat-linked chains on each side to the machine. According to the surviving text describing the repeater, the chains ran over five-sided prisms at each end of their loop. In the author’s view these prisms are assumed to have worked as inverted gears in other words, the chain-link drive for the cocking and firing sequence relied on an engagement between the lugs on the chain links and a pentagonal gear for accepting the lugs. The rear prism was turned by a winch, and the bowstring claw was locked and unlocked at the appropriate times by pegs mounted in the stock of the weapon, past which the slider moved. Hence by reciprocating the winch the device could fire arrows automatically until the magazine was empty.

    Reconstruction of the Antikythera Device

    Animations of an Antikythera device reconstruction

    Gears from the Ancient Greeks

    Some Information about Gears (French Website)

    A ndré Wegener Sleeswyk, "Vitruvius' Odometer", Scientific American 245(4) October, 1981, pp. 188-200
    http://www.database.com/

    Price D. de S. (1959) “An Ancient Greek Computer”, Scientific American p. 60-67

    Lewis, M. J. T. (1983) “Gearing in the Ancient World” Endeavour, p. 110-115
    Brian Hayes , On the teeth of Wheels , Computing Science, American Scientist (PS File)


    Mechanism

    The polybolos would have differed from an ordinary ballista in that it had a wooden magazine over the mensa (the cradle that holds the bolt prior to firing) capable of holding several dozen bolts. The mechanism is unique in that it is driven by a flat-link chain connected to a windlass the flat-link chain is an invention more often attributed to Leonardo da Vinci.

    When loading a new bolt, the windlass is rotated counter-clockwise with the trigger claw raised this drives the mensa forward towards the bow string, where a metal lug pushes the trigger under the trigger claw, which is closed over the string.

    Once the string is locked into the trigger mechanism, the windlass is then rotated clockwise, drawing the mensa back, drawing the bow string with it.

    A round wooden pole in the bottom of the magazine is rotated down toward the mensa as it is drawn to the back of the polybolos, dropping a single bolt into the tray, ready to be fired. As the mensa is twisted farther back, it meets another lug like the one that locked the string into position. This one pushes the trigger and automatically fires the polybolos, and the process is repeated. The repetition provides the weapon's name, in Greek "πολυβόλος", "throwing many missiles", [4] from "πολύς" (polys), "multiple, many" [5] and -βόλος – -bolos "thrower", in turn from "βάλλω" (ballo), "to throw, to hurl", [6] literally a repeating weapon.


    Watch the video: GROUNDBREAKING Inventions From Ancient Greece