The “philosopher’s stone” was an amazing invention of Heron of Alexandria that “changed” one liquid into another, for example, water into wine.

It consisted of an airtight vase of water which, at the top, had a tubular opening where water entered and reached the bottom and of an airtight vase of wine which, in the middle, had a tap in a siphon shape. The two vases were connected by an intermediate small tube that entered the bottom and reached close to their top. When a certain amount of water was poured into the first vase, the air inside went through the intermediate tube to the second vase pushing out the equal amount of wine. (The tube arrangement did not allow the mixing of liquids).

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The “hippaphesis” of Kleoitas was a brilliant mechanism that allowed the different time but fair start of chariots and horses in chariot races and horse races at the hippodrome of Ancient Olympia.

The mechanism ensured the starting of many chariots that were arrayed in pairs, one behind the other, in the extensive starting line of the hippodrome, which had the form of a prow of a boat (Λ). The operator of the mechanism unlatched the sand clepsydra at the end of the starting line, therefore, the bronze dolphin lowered slowly turning the drums in an altar with ropes while a bronze eagle that was on this raised to the sky.

Simultaneously, with the help of timed ropes in calculated time intervals (depending on the time needed to cover the distance between each chariot), the rope obstacles from the tracks fell in succession and the chariots set off.

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The  hysplex was a starting mechanism used in ancient Greece during the Olympics and other athletic competitions in order to prevent the false start of the athletes.

It consisted of two vertical stakes fixed to the starting line, bearing two horizontal ropes (one at the height of the knees and the other at the height of the athletes’ abdomen).

When the starter pulled the rope that released the stakes, they fell with momentum on the ground (because of the force of the twisted string at the base) thus permitting the start of the race.

The design and reconstruction of a lightweight, portable mechanism was chosen, which can operate: a) with the use of ring latches – according to the standards of the Nemean Hysplex (in this case, the starter yanked the rope upwards in order to release the rings and caused the fall of the stakes), b) with the use of hasp-bars, which applied well-known technical know-how of the siege-machines at the time (in this case, the starter pulled the rope gently in order to unhasp the stakes and cause their fall).

It is speculated that this mechanism was used in Ancient Olympia, not only at the Stadium but also during training at the Gymnasium.

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The stone throwing crane was a defensive war machine invented by Archimedes to face Roman ships in the siege of Syracuse.

It consisted of an articulated beam based on a rotating vertical beam or platform.   At one end of the beam was a counterweight and at the other end was a load  suspended by rope (for example, a large stone or a lead weight).

When not in use,the machine was laid alongside the wall in a horizontal position (so as not to be visible from the sea), wound and secured by rope and a manual winch (for balancing the counterweight).

When a ship approached the wall, the operators released the winch so that the end would gradually ascend enabling the load to pass over the wall by rotating the balance beam (via horizontal levers). When the load was above the ship, the rope was cut so that it would fall onto the target with great force.

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The fire pump of Heron was a twin suction force piston pump of continuous water flow that was used for firefighting and continued identically having the same use until recently.

It consisted of two pistons that reciprocated oppositely with the help of a pivoted common lever within two vertical cylindrical containers sunken in the (probably wheeled) water tank.

The non-return valves of the incoming water were in the raised bottom of the containers and the non-return outlet valves were at the base of the discharge pipes. The pipes converged to a common vertical pipe.  At the end of the pipe there was an ingenious (horizontally and vertically) rotating pipe system with a nozzle that allowed the precise aim of the target.

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The “iron hand” was an impressive defence war machine invented by Archimedes to face Roman ships in the siege of Syracuse.

It consisted of a jointed beam based on a rotating vertical beam or platform.  At one end of the beam there was a grappling hook (“iron hand”) which hovered by chain and at the other end a sliding counterweight.

When not in use, the machine was laid alongside the wall in a horizontal position (so as not to be visible from the sea), wound and secured by rope and a manual winch (for the balancing of the counterweight).

When a ship approached the wall, the operators threw the hook against it and rotated the vertical beam (via horizontal levers).  Once the hook caught the ship, the operator, by pulling a special lever, (“kataklis”) released the rope balancing the counterweight and the end of the beam, which accommodated the counterweight, descended to the ground while the other end, accommodating the hook, ascended overthrowing or elevating the hooked ship.

With the inclination of the horizontal beam, the counterweight slid rearwards, executing even more torque and tilt to the beam.  When the sliding counterweight reached the end and only after the beam was stabilised, the operators cut the rope holding the chain of the hook so that the hovering ship would be crushed against the water or adjacent rocks.

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The ditch-filling tortoise of Diades  was used in sieges for the levelling of ground and the filling of defensive ditches for easier approach of other siege machines.

It consisted of  a wooden cage on wheels and a hipped roof covering approximately 120 square metres for the protection of the digging and ditch-filling crew.

The exposed walls were covered with iron sheets, fresh wickerwork, clay mixed with hair, and padded rawhide and lambskins (stuffed with vinegar-soaked chaff or green seaweed) in order to neutralise incendiary arrows and to absorb the blow of stones launched by the enemy.

An ingenious placement system of the axle wheel bearing allowed its forward, sideway and diagonal movement. On another tortoise, the digging tortoise, the front face was vertical to enable better contact with the wall and easier sabotage by the diggers.

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The catapult was realised for the Rhodians.  It was equipped with a turning roller that had two grooves (one lengthwise and one helical) and a wooden case that held the launch arrows.  Also,  at both sides of its case it had two pairs of pentagonal sprockets (gears) that were connected with a wooden chain.  A pin on each chain was connected at the same point with the slider of the catapult.

The slider had a bent axle with its end entering the helical groove of the roller above.  With the right rotation (by the operator of the weapon) of the handspikes at the rear sprockets the slider moved automatically forwards, the roller turned left automatically until the lengthwise groove was aligned with the corresponding opening of the arrow case and then an arrow fell into the groove of roller.

At the same time the string entered automatically into the claw of the slider and a stable pin pushed the trigger automatically and locked the claw.  With the left rotation of the sprockets the slider moved automatically backwards, the roller turned right automatically until the lengthwise groove was aligned with the receiver of the slider and the arrow fell automatically into this.  Simultaniously,  a stable pin pressed the trigger automatically and the claw was lifted. Then the string was released automatically and the arrow was launched.

With the continuous backward and forward movement of the handspikes in this way and in minimal time the operator launched in succession the all arrows of magazine.

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The “helepolis” of Epimachos was a giant siege tower of roughly 40 metres in height that was constructed by Epimachos the Athenian and was utilised by Demetrius Poliocretes in the siege of  Rhodes (304 BC).

It consisted of nine storeys with windows and had enormous stone-projecting catapults on the lower levels and lighter ones on the upper.  It had two staircases (one for the ascent and one for the descent of the crew) and one sliding or opening boarding bridge for the mounting of soldiers onto the enemy wall.

The machine sat on eight solid wheels fitted onto a mesh undercarriage (“escharion”) with approximately 800 openings for the positioning of an equal amount of men who pushed it towards the enemy wall.  The bearings of the wheel axles (“hamaxipous”) were placed on lever-turning bases (Castor type) allowing the movement to all directions.  The front and side walls were covered with iron sheets and padded rawhide (stuffed with vinegar-soaked chaff or green seaweed) in order to neutralise incendiary arrows and to absorb the blow of stones launched by the enemy.

For its propulsion, the machine probably employed reinforcement with: a) a huge manually-operated winch used to pull the rope which was anchored to the ground beneath the front part of the machine (as in the helepolis of Posidonius) and b) a rope system secured to the rear of the undercarriage (“escharion”).  After the ropes had gone around the pulleys which were anchored to the ground (beneath the front part of the machine), they were drawn by pulley-brocks, a hauling crew and draught animals which were positioned at a safe distance behind it.

The helepolis was the evolution of the Macedonian siege towers of Polyidus of Thessalia (for Philip II) and of Diades and Charias (for Alexander) and offered besiegers the possibility to attack enemy walls but also targets in the city behind them from a safe and advantageously higher position.

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In the ancient world, until the end of the 5th century, innovations in the art of defence and siege were minimal. The safety of walls, the numerical supremacy, but mainly the bravery of soldiers was usually the chief comparative advantage of opponents.  However, the Greeks managed to change the facts in this sector, as well.

The beginning was in Syracuse in 399 BC (during the rule of Dionysius the Elder) with the systematised aid of technology in defence of the city. In the decades that followed, a multitude of engineers experimented with the result being the production of the “oxybeles” catapults (launchers of arrows and small stones of long range and powerful impact force) but also other machinery such as the incredible war machines of Archimedes ranking at the top.

Yet, the greatest drive of siege art was realised by the Macedonians (Philip II, Alexander the Great and his Successors) with the production of the powerful catapults but also with the invention of the astonishing and impressive siege machines. At that time, they also constructed the remarkable armoured vehicles (“tanks”), such as the giant siege towers (“helepolis”), the all-powerful roofed “rams”, the effective “borers”, etc.

The leading achievement of that period, however, was the “polybolos” catapult of the Rhodians (a mechanism for the continuous automatic launching of arrows).

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