Alexandria Archives - Kotsanas Museum

Archimede’s burning mirrors

admino — Tue, 09 Apr 2024 10:10:29 +0000

It is a hypothetical reconstruction of the renowned burning mirrors of Archimedes. Several ancient Greek writers, including Archimedes, had written books “on burning mirrors”, but none of them have survived. Some medieval writers describe the burning of the Roman fleet by Archimedes using such mirrors, though it is not mentioned by ancient writers. One of them, Ioannis Tzetzes (1110-1180 A.D.) describes the burning of ships, from a distance within an arrow’s range, with the help of large hexagonal mirrors invented by Archimedes. He also mentions that these large hexagonal mirrors consisted of smaller mirrors, adjusted to the main one by means of blades and joints. This remarkable description indicates an adjustable mirror with variable focus. Although the alleged burning of ships is considered a myth, it would be quite possible to set moving ships on fire using large mirrors with adjustable focus. The reconstructed mirrors, using the right placement of pulleys (or gears alternatively) and the easy rotation of a single rope, follow an adjustable parabolic path, constantly changing its focus, according to the operator’s will. Archimedes had all the necessary knowledge in Mathematics and Engineering, as well as the technological skills in order to construct them.

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The “aeolosphere” of Heron

admino — Tue, 09 Apr 2024 10:08:35 +0000

It is the precursor of the steam-turbine which, with the addition of a pulley, would have led the Hellenistic Era (had it not been interrupted by the political, economical and social factors) to the Industrial Revolution with unforeseeable consequences for humanity. It consisted of a sphere (with two curved nozzles) which rested on the curved ends of two pipes connected to the top of an airtight boiler. When the water in the boiler was heated, it turned into steam. Then, it entered the sphere and came out with speed from the two nozzles forcing the opposite continuous rotation of the sphere.

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The “varvitos” (barbitos)

admino — Tue, 09 Apr 2024 10:10:37 +0000

It was a stringed instrument which accompanied symposiums and Dionysian rituals. The soundbox was of tortoise shell as the lyre. The arms, however, were much longer with longer strings (5 until 7) and consequently had a deeper pitch and a softer tone than that of the lyre. Its straight wooden arms rose outward from its base and curved inward at the top with a bent end which carried the cross-bar. The elasticity of the arms allowed them imperceptible vertical motion thus creating a wave-like resonance. The player balanced the barbitos upright against the left side of his body pressing it laterally against his belly (with the help of a sling which went through the left arm of the instrument and his left wrist). The free fingers pressed or plucked its strings while the right hand struck them with the “plectrum”. Anacreon, Sappho and Alceus established the barbitos (“varmos”) between the 6th and the 5th century B.C.

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The (automatic) magic fountain of Heron

admino — Tue, 09 Apr 2024 10:07:46 +0000

It was a brilliant fountain which shot recycled water higher than the available level of its reservoir defying ostensibly the principles of hydrostatic pressure and communicating vessels. It consisted of one open and two airtight containers placed one above the other. The middle airtight container was full with water and a pipette began a little above its bottom and led to a nozzle above the upper open container. When some water was poured into the upper open container, this, through a pipe, flowed into the lower airtight container. The confined air therein was pressed and through another pipe it displaced the water of the middle container, forcing it to rise to the nozzle and to shape a small spurt. The spurt of water supplemented the water of the upper container (maintaining the level constant). Thus, this process was self-supporting and it continued automatically until all the water from the middle container emptied.

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The automatic goblet of Philon

admino — Tue, 09 Apr 2024 10:12:31 +0000

It was an invention of Philon of Byzantium which always kept a goblet of wine full, regardless of the quantity removed. It consisted of an air-tight vessel full of wine with a horizontal tube-tap that led to a goblet. The perforated bottom of the goblet led to a hollow base (horizontal piping with a vertical tube that reached the height of the goblet). A smaller tube that started from the top of the air-tight vessel penetrated its bottom and entered the vertical tube of the hollow base in a depth equivalent to the desired level of the wine in the goblet. The level of the wine in the vertical tube of the hollow base fell after the removal of a certain quantity of wine from the goblet, thus, allowing the entrance of air through the smaller tube in the air-tight vessel. This led to the flow of wine towards the goblet and to the increase of its level in the hollow base. When the level of the wine reached the mouth of the smaller tube of the vessel it created vacuum and the flow stopped.

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The automatic holy water server with coin-acceptor

admino — Tue, 09 Apr 2024 10:07:14 +0000

It is the oldest automatic vending machine in history. It was placed outside temples and allowed the faithful to obtain holy water by dropping a five-drachma coin into a vessel. The coin fell onto the disc of a balance, the diversion of which opened a conical valve and certain amount of water out flowed.

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The automatic servant of Philon

admino — Tue, 09 Apr 2024 10:07:06 +0000

This was a humanoid robot in the form of a female servant (life-size) which in her right hand held a jug of wine. When the visitor placed a cup in the palm of her left hand, she automatically poured wine, initially, and then she poured water into the cup mixing it when desired. Inside the servant, there were two airtight containers with wine and water, respectively. At their bottom there were two tubes leading their content through her right hand to the lip of the wine jug. Two air pipes started at the top of the containers, went through their bottom and led curved into her stomach. Her left arm was connected, through the articulation, to her shoulders; while a helical rod (spring) that was positioned in extension of the restraining rod raised it. Two pipes started at the same point (joint) and came down penetrating and freeing the curved perforated ends of the air pipes. The pipes of the joint had two holes at their ends, with the hole that communicated with the wine container preceding that which communicated with the water container. When the cup was placed into the servant’s palm, her left hand came down and the tubes of the joint lifted. The hole in one pipe was aligned with the air pipe of the wine container, air entered the container and wine flowed from the tube into the cup. When the cup of wine was half- full, the hand (due to weight) descended further, the passage of the air pipe of wine was obstructed and the flow stopped. At the same time the other tube was aligned with the air pipe of the water container and it began to flow, thus, diluting the wine. When the cup was full, the hand (due to weight) descended further, the passage of the air pipe with water was obstructed and the flow stopped. Also, if the cup was removed at any moment, the left hand rose, the tubes of the joint descended, cutting off the air pipes, creating vacuum in the containers and stopping the liquid flow. The servant then filled the visitor’s cup with wine or diluted with water of desired quantity depending on the time it was pulled from her palm.

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The fire pump of Ktesibios and Heron

admino — Tue, 09 Apr 2024 10:07:38 +0000

It 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 hand lever within two vertical cylindrical containers immersed 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 hydraulic automaton of Pan and of the thirsty dragon or deer

admino — Tue, 09 Apr 2024 10:12:23 +0000

It was a conception of Philon of Byzantium depicting a dragon or a deer that drank water with great hunger and roared only when Pan turned away from it. When Pan turned, the dragon relaxed. The theme was repeated continuously. For the operation of the automaton, water from a spring was driven inside the airtight intermediate container, forcing air to leave towards the built-in tube of the dragon or the deer giving a roaring impression. Then, when the water level exceeded the axial siphon, it emptied through it to the lower container, therefore, because of the vacuum created by the emptying of the container, the tube incorporated in the deer sipped water and air giving the drinking impression. If Pan turned to the deer, the water from the spring was driven by the rotating horizontal pipe directly into the lower container, the phenomenon ceased and the water level in the large krater (bowl) rose.

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The hydraulic automaton of the “chirping birds” and of the “returning owl”

admino — Tue, 09 Apr 2024 10:07:30 +0000

It was a conception of Philon of Byzantium (which was improved by Heron of Alexandria) depicting birds chirping, when an owl turned away from them and they stopped frightened, when it turned towards them. Automatically, the theme was repeated continuously. For the operation of the automaton, water from a spring was driven inside the upper airtight container forcing the air to leave through a pipe. Because the pipe led to water, the vibrating wavelength produced a chirp with notes of different frequency. Then, when the water level exceeded the curved siphon of the container, it emptied through it to the intermediate container, diverting a yoke to its side. This forced the built-in rotating shaft supporting the owl to turn towards the birds that then stopped chirping. When the water level exceeded the axial siphon of the intermediate container, it emptied through to the lower container, diverting the yoke towards its counterweight, which caused the owl to turn away from the birds that then began to sing again, etc.

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