Ancient Greek steam engine of Heron of Alexandria. Heron. Eliopil, piston pump, boiler

Archimedes' doctrine of the equilibrium of liquids was used in the brilliant inventions of Heron of Alexandria, to which we now turn.

Heron of Alexandria, a student of Ctesibius, the son of a barber and also a skilled inventor, lived in the second half of the 2nd century. BC e. (about 120 g). In the person of Heron we are dealing with a practitioner of ancient science. In the field of mathematics, Heron searched for relationships that would best suit the purposes of land surveying, and developed calculation methods, in particular methods of approximate calculations. He gave a rule to determine the area of a triangle based on its sides; in its modern form, this rule is written in the form of the so-called Heron’s formula:

Heron's inventions were not of the nature of technical applications; they can rather be called technical toys, and their history is an instructive example of how ingenious inventions that do not meet the needs of the era remain fruitless.

Heron's teacher - Ctesibius, as already mentioned, he was a major inventor. He invented a water clock with a pointer (Fig. 28), a water organ, and a fire engine. The latest invention had an almost modern appearance. Heron describes this machine as follows:

“Fire pumps used to extinguish fires are made as follows (Fig. 29): two metal cylinders are drilled from the inside with a lathe according to the size of the piston, just as a master’s “pumps” are drilled out for wells. KL and MN are precisely fitted pistons. Cylinders connected to each other by a pipe XODE and provided externally (inside the pipe XODE,) - valves P and R that open outward. In the bottom of the cylinders there are holes S and T, which are closed by smooth hinge plates (valve flaps); bolts are passed through them, which are firmly soldered or firmly connected to the bottom of the cylinder using rivets placed on their outer ends. The pistons are equipped with rods S fixed in the middle; a rod (balancer Za) is connected to them, which in the middle rotates around the bolt; the piston rods S rotate around bolts b and v. Above the hole in the XODEy tube, another vertical fork-shaped tube S is installed, equipped with a faucet-like nozzle, through which water is thrown out in the same way as we already said above when describing the vessel that threw out water using air compressed in it.”

The valve mentioned in this description (Fig. 30) was apparently also invented by Ctesibius. Heron describes this device as follows: “Two quadrangular plates of appropriate thickness are made, finger-length on each side. With their surfaces they are fitted to each other and ground so that neither air nor water can pass between them. Let these plates be ABCD and EFGH. In one of them, namely ABCD, a round hole is drilled one-third of a finger wide. The edge CD is connected by a hinge to the edge FE, so that the ground sides of the metal plates lie on top of each other. When they want to use these valves, the plate ABCD "soldered tightly to the hole through which air or water must enter. In this case, when pressure from the inside, the EFGH plate opens and allows air or water to pass through. But then the pressure of the air or water will press the EFGH plate against the hole through which air or water enters."

As we can see, technology, in particular metal processing technology, reached a fairly high level at this time. Below we will see that Heron even implemented a heat engine. But this technology, as has been repeatedly pointed out, could not bring about an industrial revolution, could not play the revolutionary role that it played during the period of primitive accumulation, during the period of bourgeois revolutions.

Heron's famous inventions are described in the treatise "Pneumatics" that has come down to us. In his theoretical positions, Heron is aligned with Aristotle, but with significant amendments. He, like Aristotle, believes that there is no emptiness in nature, but “although there is no large empty space in nature, nevertheless very small empty spaces exist in liquids, fire and other bodies.”

Heron considers elasticity, mixing of various liquids, expansion of bodies due to heating, etc. as proof of the existence of empty spaces between particles. Heron considers air to be a body consisting of very light and mobile particles. Heron believes that proof that air is a body is, for example, the fact that a vessel turned upside down when immersed in another vessel with water does not fill with water. If a hole is made in the bottom of the vessel through which air can escape, then water will fill the inside of the immersed vessel, displacing the air through this hole. Nature does not allow abnormally large gaps between the particles of the body and, in this sense, is “afraid of emptiness.” So, for example, if a certain amount of air is sucked out of a vessel, due to which the distance between the particles of the remaining air increases, then the vessel will have suction properties (blood-sucking cups): the skin of the finger covering the hole of the vessel will be drawn inward. If the finger is removed, outside air enters the vessel, filling its volume until the distances between the particles reach a normal value. In this we should look for the reasons for the strength of bodies. A liquid stream, according to Heron, also has tensile strength *. Once a column of liquid has arisen, it cannot rupture, because this would lead to the formation of a significant void. This is the basis of Heron's explanation of the action of the siphon.

* (Galileo, in his doctrine of the strength of materials, restored the views of Heron.)

Let's immerse the elbow tube AHDBCKL (Fig. 31) in a vessel filled with water to level FG. The water in the knee will reach the I level, which coincides with the FG level. If you suck air from L with your mouth, then, due to the indicated property of not allowing significant voids, the air will suck water from the vessel along the knee AHD. If the vacuum is sufficient, water will fill the upper part of tube B and begin to flow down the elbow CKL. Trying to fall like a weight in both knees, it cannot fall, because this would lead to a rupture of the jet. If the fluid level in the left knee is lower than in the right, then the left load of water will pull over the right one and the water will flow from a higher level to a lower one until the fluid levels on the left and right are equal, or until it is emptied vessel (if its bottom level is high enough).

So, in Heron’s theory we are dealing with two main assumptions: a) the impossibility of breaking the jet, b) the overhang of the jet by a longer part, which leads to the flow of liquid from a higher level to a lower one. Once the resulting liquid stream behaves like a rope thrown over a block. The rope will "run" towards the longer part. Outside air pressure does not play a role in this explanation.

It is curious that this explanation of Heron was relatively recently restored as the newly discovered “principle of action of the liquid siphon.” In Professor Pohl's book "Introduction to Mechanics and Acoustics" we come across the statement emphasized by the author that "the siphon principle has nothing to do with air pressure", in explanation of which (i.e. the statement) an image of a chain running off a block is given. Leaving aside the reticence of Prof. Fields about the fact that the principle he put forward against the usual “elementary” interpretation of the action of the siphon dates back two thousand years, we note that prof. Paul also passes over in silence some of the difficulties associated with Heron's explanation, difficulties that were already known to Heron himself. Namely, if you imagine that the left end of the chain is shorter, but consists of several chains, then you can not only achieve balance, but also the chain running towards the short part. In other words, if you make a siphon tube from elbows of unequal thickness, making the short elbow thicker, you can achieve a transfusion of liquid from a lower level to a higher one. Heron points out that this is impossible. Fill the U-shaped tube with liquid to the very top. Let's close the ends of the tube and tip it into two vessels with unequal levels of liquids so that the thick elbow of the tube is immersed in the vessel with the highest level of liquid. By removing the fingers from the ends of the tube, we will establish communication between the masses of liquid in both vessels (the column of liquid in the siphon tube cannot break). But, according to Archimedes, the communicating masses of liquid will be in equilibrium if and only if the free surface is a spherical surface with its center at the center of the Earth. Consequently, liquid will flow from the highest level to the lowest until the levels become equal. We see that Heron, starting from Archimedes, essentially formulates the principle of communicating vessels. As for the principle of the siphon, Heron's explanation, restored by Paul, reflects one aspect of the siphon's operation, but not all. Pascal's research represents a major step forward in understanding the action of the siphon, and not a step back, as Prof. wants to say. Paul. Heron’s peculiar understanding of the “fear of emptiness” gives him the opportunity to explain the action of the pipette, which for him has the shape of a “magic ball”. If, leaving the top hole open, you immerse the ball in liquid, then the liquid will enter through the holes in the bottom of the ball into it. If you now close the hole with your finger and remove the ball, the water will not pour out through the lattice bottom of the ball, because this would lead to the formation of voids in the internal air space. By removing your finger, you can pour the liquid anywhere.

Heron invented siphons of various shapes. We will mention here the double siphon and the siphon with a constant flow rate (siphon with a float). A double siphon (Fig. 32) is a tube that is closed at the top but open at the bottom. A second tube is placed inside this tube, open at both ends; the upper end does not reach the bottom of the outer tube. If the vessel has a hole in the bottom of such a size that the inner tube of the siphon fits into it, tightly fitting to the edges, then liquid can be poured into the vessel until its level is such that the outer tube of the siphon is filled to the very bottom . Then, according to the siphon principle, the liquid will flow through the inner tube until the vessel is empty. The double siphon explains the action of Heron's "magic cup". In a siphon with a constant flow rate (Fig. 33). the inner elbow is fixed in a bowl floating on the surface of the liquid in the vessel. As the liquid level decreases, the siphon also lowers, so that the outlet remains below the liquid level always by the same amount. As an example to illustrate Heron’s ingenuity, let us describe his “singing bird” machine gun (Fig. 34). The bird whistles when the owl is not looking at it, and falls silent when the owl turns to it. The operation of this device is based on the appropriate selection of double siphons. When liquid flows through the funnel into the upper vessel, it displaces air, which, passing through the tube, causes a whistle. As the liquid level in the reservoir rises, it begins to flow through the siphon into the lower bucket. This will eventually overload the bucket, which will pull on the counterweight and cause the owl to turn. The siphon is selected so that at this moment the flow out of the reservoir exceeds the rate of liquid inflow - the bird does not sing. Then the lower siphon comes into action. As the tank empties, the bucket will also empty - the owl will turn away. The machine starts working again.

It is especially remarkable that Heron was the first to use the driving force of heat. Let us first get acquainted with the effect of his “Aeolipile”. Heron's aeolipile is an iron ball that can rotate around a horizontal axis (Fig. 35). At the top of the ball there is an outlet tube bent at a right angle; the same tube, but bent in the opposite direction, is located at the bottom of the ball. The steam coming from the tank through the side pipes is expelled by the outlet pipes. The reaction of the steam jet (turbine principle) causes the ball to rotate.

Thus, almost two thousand years before the invention of the steam engine, a heat engine was first constructed. But this was a premature invention, and a new search for a heat engine began in the 17th century.

Let us give as an example of the use of the driving force of heat - an altar with automatically opening doors when the sacrificial fire is lit (Fig. 36).

“In the temple there is a hollow altar DE, which is connected by means of a tube FG to a spherical vessel PH, half filled with water. A U-shaped tube KLM is soldered into the ball. The rotation axes of both door leaves are extended to the basement floor, where they are inserted into the corresponding sockets. two chains are wound on the axes. At the end of one chain a load is placed, which with its weight tends to close the door, and on the other, wound in the opposite direction on the door axes, hangs a vessel of another, wound in the opposite direction XN, which, being empty, is lighter than the load. In this vessel passes through one of the elbows of a U-shaped tube, which is so installed that when the doors are closed, this elbow extends almost to the bottom of the vessel.

When a fire is lit on the altar, the altar heats up, the air enclosed in it expands, presses on the water in the ball, and raises it through a U-shaped tube into a suspended vessel, which thereby lowers and thus opens the door.

We will limit ourselves to the examples considered. From what has been said it is clear how ingenious Heron's inventions were. Only his hydraulic machines, which improved the technology of water-drawing machines, received practical significance. The rest of the inventions served as funny toys, nothing more. Only the resurgent new science turned to Heron's inventions, developing them further on a new basis.

The age of steam engines was short-lived. But it turns out that even the ancient Greeks knew how to “tame” steam and even use it in warfare. Our close ancestors spent a lot of time and effort on mastering “steam,” and recently this topic has even received a second wind.

People were able to put steam to the service of humanity only at the very end of the 17th century. But even at the beginning of our era, the ancient Greek mathematician and mechanic Heron of Alexandria clearly showed that one can and should be friends with steam. A clear confirmation of this was the Geronovsky aeolipile, in fact, the first steam turbine - a ball that rotated with the power of jets of water vapor.

Unfortunately, many amazing inventions of the ancient Greeks were firmly forgotten for many centuries. Only in the 17th century is there a description of something similar to a steam engine.

For reference:

HERO OF ALEXANDRIAN (Heronus Alexandrinus)

Dates of birth and death are unknown, probably 1st - 2nd centuries.

Heron of Alexandria was a Greek scientist who worked in Alexandria.

The author of works that have survived to this day, in which he systematically outlined the main achievements of the ancient world in the field of applied mechanics. In his famous two-volume work “Pneumatics,” he described various mechanisms driven by heated or compressed air or steam: aeolipile, i.e., a ball rotating under the influence of steam, an automatic door opener, a fire pump, various siphons, a water organ, a mechanical puppet theater, etc. In "Mechanics" I examined in detail the simplest mechanisms: lever, gate, wedge, screw and block. Using a gear drive, he built a device for measuring the length of roads, based on the same principle as modern taximeters. He created a vending machine for selling “sacred” water, which was the prototype of our vending machines for dispensing liquids. Heron's mechanisms and automata did not find any widespread practical application and were used mainly in the construction of mechanical toys. The only exceptions are Heron's hydraulic machines, with the help of which ancient water drawers were improved.

In his essay “On the Diopter” he outlined the rules for land surveying, which were actually based on the use of rectangular coordinates. Here he also gave a description of the diopter - a device for measuring angles - the prototype of a modern theodolite. In the essay "Catoptrics" he substantiated the straightness of light rays with an infinitely high speed of propagation. He gave a proof of the law of reflection, based on the assumption that the path traversed by light should be the smallest of all possible (a special case of Fermat's principle). Based on this principle, I considered various types of mirrors. In his treatise “On the Making of Throwing Machines” he outlined the basics of ancient artillery. Heron's mathematical works are an encyclopedia of ancient applied mathematics. The Metrics provides rules and formulas for the exact and approximate calculation of various geometric figures, for example Heron's formula to determine the area of a triangle based on three sides, rules for numerically solving quadratic equations, and approximate extraction of square and cube roots.

In this article, I invite you to get to know one of the amazing scientists of antiquity. He made a huge contribution to the development of science in his time, but most of his works and inventions sank into oblivion and were undeservedly forgotten. His name is Heron of Alexandria.

Rice. 1. Heron of Alexandria

The most famous is Heron's "Metrics" - a scientific work that gives the definition of a spherical segment, a torus, rules and formulas for accurate and approximate calculation of the areas of regular polygons, the volumes of truncated cones and pyramids. The Metrics provides Heron's famous formula for determining the area of a triangle on three sides, and gives rules for the numerical solution of quadratic equations and the approximate extraction of square and cube roots. Metrics examines the simplest lifting devices - lever, block, wedge, inclined plane and screw, as well as some combinations of them. In this work, Heron introduces the term “simple machines” and uses the concept of moment of force to describe their work.

Many mathematicians accuse Heron of the fact that the Metrics does not contain mathematical proofs of the conclusions he made. This is true. Heron was not a theorist; he preferred to explain all the formulas and rules he derived with clear practical examples. It is in the area of practice that Heron surpasses many of his predecessors. The best illustration of this is his work "On the Diopter", found only in 1814. This work outlines methods for carrying out various geodetic works, and surveying is carried out using a device invented by Heron - a diopter.

Rice. 2. Diopter

The diopter was the prototype of the modern theodolite. Its main part was a ruler with sights attached to its ends. This ruler rotated in a circle, which could occupy both horizontal and vertical positions, which made it possible to mark directions in both the horizontal and vertical planes. To ensure correct installation of the device, a plumb line and level were attached to it. Using this device and introducing rectangular coordinates, Heron could solve various problems on the ground: measure the distance between two points when one or both of them are inaccessible to the observer, draw a straight line perpendicular to an inaccessible straight line, find the level difference between two points, measure the area of a simple figure without even stepping onto the area being measured.

Even in the time of Heron, the water supply system on the island of Samos, created according to the design of Eupalinus and passing through a tunnel, was considered one of the masterpieces of ancient engineering. Water through this tunnel was supplied to the city from a source located on the other side of Mount Castro. It was known that in order to speed up the work, the tunnel was dug simultaneously on both sides of the mountain, which required high qualifications from the engineer in charge of the construction. The water pipeline operated for many centuries and surprised Heron’s contemporaries; Herodotus also mentioned it in his writings. It was from Herodotus that the modern world learned about the existence of the Eupalina tunnel. I found out, but didn’t believe it, because it was believed that the ancient Greeks did not have the necessary technology to build such a complex object. Having studied Heron’s work “On the Diopter”, found in 1814, scientists received the second documentary evidence of the existence of the tunnel. It was only at the end of the 19th century that a German archaeological expedition actually discovered the legendary Eupalina Tunnel.

This is how in his work Heron gives an example of using the diopter he invented to build the Eupalina tunnel.

Fig.3. Measuring diagram for the construction of the Eupalina Tunnel

Points B and D are the entrances to the tunnel. Near point B, point E is selected, and from it a segment EF is constructed along the mountain, perpendicular to the segment BE. Next, a system of mutually perpendicular segments is built around the mountain until a line KL is obtained, on which point M is selected and a perpendicular MD is built from it to the entrance to the tunnel D. Using lines DN and NB, a triangle BND is obtained and the angle? is measured.

Among other things, in the 34th chapter of the work “On the Diopter” Heron gives a description of the device he invented for measuring distances - the odometer.

Rice. 4. Odometer (appearance)

Rice. 5. Odometer (internal device)

One of Heron's most interesting works is "Pneumatics". The book contains descriptions of about 80 devices and mechanisms operating using the principles of pneumatics and hydraulics. The most famous device is the aeolipile (translated from Greek: “ball of the wind god Aeolus”).

Rice. 6. Aeolipile

When assembling the aeolipile, scientists encountered the problem of sealing in the hinge joints of the ball and steam supply tubes. With a large gap, the ball received a greater degree of freedom of rotation, but steam easily escaped through the gaps, and its pressure quickly dropped. If the gap was reduced, the loss of steam disappeared, but the ball also became more difficult to rotate due to increased friction. We do not know how Heron solved this problem. Perhaps his aeolipile did not rotate at such a high speed as the modern model.

Unfortunately, the aeolipile did not receive due recognition and was not in demand either in the era of antiquity or later, although it made a huge impression on everyone who saw it. This invention was treated only as a fun toy. In fact, Heron's aeolipile is the prototype of steam turbines, which appeared only two millennia later! Moreover, aeolipile can be considered one of the first jet engines. There was one step left before the discovery of the principle of jet propulsion: having an experimental setup in front of us, it was necessary to formulate the principle itself. Humanity spent almost 2000 years on this step. It is difficult to imagine what human history would have looked like if the principle of jet propulsion had become widespread 2000 years ago. Perhaps humanity would have long ago explored the entire solar system and reached the stars. I confess that sometimes the thought arises that the development of humanity has been deliberately delayed by someone or something for centuries. However, we will leave this topic for development by science fiction writers...

Interestingly, the reinvention of Heron's aeolipile took place in 1750. Hungarian scientist J.A. Segner built a prototype of a hydraulic turbine. The difference between the so-called Segner wheel and the aeolipile is that the reactive force rotating the device is created not by steam, but by a jet of liquid. Currently, the invention of the Hungarian scientist serves as a classic demonstration of jet propulsion in physics courses, and in fields and parks it is used to water plants.

Another outstanding invention of Heron related to the use of steam is the steam boiler.

Rice. 7. Heron steam boiler

The design consisted of a large bronze container with a coaxially installed cylinder, a brazier and pipes for supplying cold and discharging hot water. The boiler was very economical and provided rapid heating of water.

A significant part of Heron's Pneumatics is occupied by a description of various siphons and vessels from which water flows by gravity through a tube. The principle inherent in these designs is successfully used by modern drivers when it is necessary to drain gasoline from a car tank.

As you know, in the era of antiquity, religion had a huge influence on people. There were many religions and temples, and everyone went to communicate with the gods where he liked best. Since the well-being of the priests of a particular temple directly depended on the number of parishioners, the priests tried to lure them with anything. It was then that they discovered a law that is still in force today: nothing can attract people to the temple better than a miracle. However, Zeus descended from Olympus no more often than manna from heaven fell from the sky. And parishioners had to be lured to the temple every day. To create divine miracles, the priests had to use the mind and scientific knowledge of Heron. One of the most impressive miracles was the mechanism he developed that opened the doors to the temple when a fire was lit on the altar. The principle of operation is clear from the animated drawing.

Rice. 8. Scheme of the “magical” opening of doors in the temple

Air heated from the fire entered a vessel with water and squeezed out a certain amount of water into a barrel suspended on a rope. The barrel, filling with water, fell down and, with the help of a rope, rotated the cylinders, which set the swing doors in motion. The doors opened. When the fire went out, the water from the barrel poured back into the vessel, and a counterweight suspended on a rope, rotating the cylinders, closed the doors.

Quite a simple mechanism, but what a psychological effect on parishioners!

Another invention that significantly increased the profitability of ancient temples was the holy water vending machine invented by Heron.

Rice. 9. Vending machine for selling “holy” water

The internal mechanism of the device was quite simple, and consisted of a precisely balanced lever operating a valve that opened under the influence of the weight of a coin. The coin fell through a slot onto a small tray and activated a lever and valve. The valve opened and some water flowed out. The coin would then slide off the tray and the lever would return to its original position, closing the valve. According to some sources, a portion of “sacred” water in the time of Heron cost 5 drachmas.

This invention of Heron became the world's first vending machine and, despite the fact that it brought good profits, it was forgotten for centuries. It was only at the end of the 19th century that vending machines were reinvented.

Perhaps Heron's next invention was also actively used in temples.

Rice. 10. Vessels for “transforming” water into wine

The invention consists of two vessels connected by a tube. One of the vessels was filled with water, and the second with wine. The parishioner added a small amount of water to a vessel with water, the water entered another vessel and displaced an equal amount of wine from it. A man brought water, and “by the will of the gods” it turned into wine! Isn't this a miracle?

And here is another vessel design invented by Heron for converting water into wine and back.

Rice. 11. Amphora for pouring wine and water

Half of the amphora is filled with wine, and the other half with water. Then the neck of the amphora is closed with a stopper. The liquid is extracted using a tap located at the bottom of the amphora. In the upper part of the vessel, under the protruding handles, two holes are drilled: one in the “wine” part, and the second in the “water” part. The cup was brought to the tap, the priest opened it and poured either wine or water into the cup, quietly plugging one of the holes with his finger.

A unique invention for its time was a water pump, the design of which was described by Heron in his work “Pneumatics”.

Rice. 12. Heron pump

The pump consisted of two communicating piston cylinders equipped with valves from which water was alternately displaced. The pump was driven by the muscular power of two people, who took turns pressing the arms of the lever. It is known that pumps of this type were subsequently used by the Romans to extinguish fires and were distinguished by high quality workmanship and amazingly precise fit of all parts. Until the discovery of electricity, pumps similar to them were often used both for extinguishing fires and in the navy for pumping water from holds in the event of an accident.

As we can see, Heron developed three very interesting inventions: the aeolipile, the piston pump and the boiler. By combining them it was possible to get a steam engine. Such a task was probably within the power, if not of Heron himself, then of his followers. People already knew how to create sealed containers, and, as can be seen from the example with the piston pump, they achieved significant success in the manufacture of mechanisms that required high precision manufacturing. A steam engine, of course, is not a jet engine, for the creation of which the knowledge of ancient scientists was clearly lacking, but it would also significantly accelerate the development of mankind. Why didn't this happen?

The most common method of lighting in ancient times was using oil lamps, in which a wick soaked in oil burned. The wick was a piece of rag and burned out quite quickly, and so did the oil. One of the main disadvantages of such lamps was the need to ensure that there was always enough wick above the surface of the oil, the level of which was constantly decreasing. If with one lamp it was easy to keep track of it, then with several lamps there was already a need for a servant who would regularly walk around the room and adjust the wicks in the lamps. Heron invented an automatic oil lamp.

Rice. 13. Heron's oil lamp

The lamp consists of a bowl into which oil was poured and a device for feeding the wick. This device contained a float and a gear connected to it. When the oil level dropped, the float dropped, rotated the gear, and it, in turn, fed a thin rail wrapped with a wick into the combustion zone. This invention was one of the first uses of a rack and pinion gear.

Another invention of Heron, intended for temples, was an organ powered by the wind.

Rice. 14. Hydraulos, modernized by Heron

The organ created by Heron was not original, but was only an improved design of the hydraulos, a musical instrument invented by Ctesibius. Hydraulos was a set of pipes with valves that created sound. Air was supplied to the pipes using a water tank and a pump, which created the necessary pressure in this tank. The valves of the pipes, as in a modern organ, were controlled using a keyboard. Heron proposed to automate the hydraulic system using a wind wheel, which served as a drive for a pump that forced air into the reservoir.

Those who were lucky enough to have a school physics teacher probably know about the famous Fountain of Heron.

Rice. 15. Fountain of Heron

Heron's Fountain consists of three vessels, placed one above the other and communicating with each other. The two lower vessels are closed, and the upper one has the shape of an open bowl into which water is poured. Water is also poured into the middle vessel, which is later closed. Through a tube running from the bottom of the bowl almost to the bottom of the lower vessel, water flows down from the bowl and, compressing the air there, increases its elasticity. The lower vessel is connected to the middle one through a tube through which air pressure is transmitted to the middle vessel. By exerting pressure on the water, the air forces it to rise from the middle vessel through the tube into the upper bowl, where a fountain emerges from the end of this tube, rising above the surface of the water. The fountain water falling into the bowl flows from it through a tube into the lower vessel, where the water level gradually rises, and the water level in the middle vessel decreases. Soon the fountain stops working. To start it again, you just need to swap the lower and middle vessels. The operation of the fountain is clearly demonstrated in this video file.

Heron's Pneumatics also describes the design of a syringe.

Rice. 16. Syringe of Heron

Unfortunately, it is not known for sure whether this device was used for medical purposes in ancient times. It is also unknown whether the Frenchman Charles Pravaz and the Scotsman Alexander Wood, who are considered the inventors of the modern medical syringe, knew about its existence.

For the first time in history, Heron developed a self-propelled mechanism.

Rice. 17. Self-propelled cabinet

The mechanism was a wooden cabinet mounted on four wheels. The interior of the cabinet was hidden behind the doors. The secret of movement was simple: a suspended plate was slowly lowered inside the cabinet, setting the entire structure in motion with the help of ropes and shafts. A supply of sand was used as a speed regulator, which was gradually poured from the top of the cabinet to the bottom. The speed of lowering the slab was regulated by the speed of sand pouring, which depended on how wide the doors were opened, separating the upper part of the cabinet from the lower.

A unique scientific work for its time is Heron's Mechanics. This book has come to us in the translation of an Arab scholar of the 9th century AD. Costa al-Balbaki. Until the 19th century, this book was not published anywhere and was apparently unknown to science either during the Middle Ages or during the Renaissance. This is confirmed by the absence of lists of its text in the original Greek and in the Latin translation, and the lack of mention of it among scholastic authors. In Mechanics, in addition to describing the simplest mechanisms: wedge, lever, gate, block, screw, we find a mechanism created by Heron for lifting loads.

Rice. 18. Barulk

In the book this mechanism appears under the name baroulkos. From the figure it can be seen that this device is nothing more than a gearbox, which is used as a winch. Heron's barulcus consists of several gear wheels driven by hand, and Heron takes the ratio of the diameter of the wheel to the diameter of the axle to be 5: 1, having previously assumed that the load to be lifted weighs 1000 talents (25 tons), and the driving force is equal to 5 talents ( 125 kg).

Heron dedicated his works “On Military Machines” and “On the Manufacturing of Throwing Machines” to the basics of artillery and described in them several designs of crossbows, catapults, and ballistas.

Rice. 19. Ballista (modern reconstruction)

If Heron's works in mathematics and engineering made him famous among a narrow circle of scientists of the time, then among the general public he was known for his automatic theaters. Heron's works evoked in people a sense of surprise and admiration for the possibilities of technical thought. Many of his creations served educational purposes and demonstrated not only the possibilities of science, but also introduced contemporaries to the facts of history and myths of Hellas.

Heron's work "On Automata" was popular during the Renaissance and was translated into Latin, and was also cited by many scientists of that time. In particular, in 1501 Giorgio Valla translated some fragments of this work. Later translations followed by other authors.

There is a known image of one of Heron’s automata, which was given in his book in 1589 by Giovanni Battista Aleoti. This video file presents a reconstruction of one of Heron's movable automata.

Rice. 20. One of Heron’s machine guns

Most of the drawings of Heron's mechanical dolls have not survived, but various sources contain descriptions of them. It is known that Heron created a kind of puppet theater, which moved on wheels hidden from the audience and was a small architectural structure - four columns with a common base and architrave. The puppets on his stage, driven by a complex system of cords and gears, also hidden from public view, reenacted the ceremony of the festival in honor of Dionysus. As soon as such a theater entered the city square, a fire flared up on its stage above the figure of Dionysus, wine poured from a bowl onto the panther lying at the feet of the deity, and the retinue began to dance to the music. Then the music and dancing stopped, Dionysus turned in the other direction, a flame flared up in the second altar - and the whole action was repeated all over again. After such a performance, the dolls stopped and the performance ended. This action invariably aroused interest among all residents, regardless of age. But the street performances of another puppet theater, Heron, were no less successful. This theater (pinaka) was very small in size, it was easily moved from place to place. It was a small column, at the top of which there was a model of a theater stage hidden behind the doors. They opened and closed five times, dividing into acts the drama of the sad return of the victors of Troy. On a tiny stage, with exceptional skill, it was shown how warriors built and launched sailing ships, sailed on them on a stormy sea and died in the abyss under the flash of lightning and thunder. To simulate thunder, Heron created a special device in which balls spilled out of a box and hit a board.

Rice. 21. Thunder Simulator

In his automatic theaters, Heron, in fact, used elements of programming: the actions of the machines were performed in strict sequence, the scenery replaced each other at the right moments. It is noteworthy that the main driving force that set the theater's mechanisms in motion was gravity (the energy of falling bodies was used); elements of pneumatics and hydraulics were also used. Springs, which became so widely used in Renaissance machines, were not used. The reason for this is simple: the production of springs requires high-quality steel alloys with elasticity, which were not known to the metallurgists of antiquity.

Throughout his life, Heron created many different inventions that were interesting not only to his contemporaries, but also to us - living two millennia later. In this article, the author presented only the most famous of them, and you can find descriptions of other equally interesting inventions (for example, a boiler, a pneumatic door opening alarm) using the sources listed below.

Bathyscaphe O. PicardLiterature

1. Michael Lahanas "Heron of Alexandria" http://www.mlahanas.de/Greeks/HeronAlexandria.htm

2. The Pneumatics of Hero of Alexandria (from the original greek translated for and edited by Bennet Woodcroft)http://www.history.rochester.edu/steam/hero/index.html

3. An Aeoli- What?!? by Katie Crisalli http://www.pr.afrl.af.mil/aeolipile.html

4. Ancient Inventions http://www.smith.edu/hsc/museum/ancient_inventions/hsclist.htm

5. Technical Works by Heron of Alexandria, Aristides Quintilianus and Johannes Pediasimos, with diagrams, later 16th century http://image.ox.ac.uk/show?collection=magdalen&manuscript=msgr12

Many of us, studying physics or the history of technology, are surprised to discover that some modern technologies, objects and knowledge were discovered and invented in ancient times. Science fiction writers in their works even use a special term to describe such phenomena: “chronoclasms” - mysterious penetrations of modern knowledge into the past. However, in reality everything is simpler: most of this knowledge was actually discovered by ancient scientists, but then for some reason they were forgotten about and rediscovered centuries later. In this article, I invite you to get to know one of the amazing scientists of antiquity. He made a huge contribution to the development of science in his time, but most of his works and inventions sank into oblivion and were undeservedly forgotten. His name is Heron of Alexandria.

Heron lived in Egypt in the city of Alexandria and therefore became known as Heron of Alexandria. Modern historians suggest that he lived in the 1st century AD. somewhere between 10-75 years. It has been established that Heron taught at the Alexandria Museum, a scientific center of ancient Egypt, which included the famous Library of Alexandria. Most of Heron's works are presented in the form of comments and notes to training courses in various academic disciplines. Unfortunately, the originals of these works have not survived; they may have perished in the fire that engulfed the Library of Alexandria in 273 AD, and they may have been destroyed in 391 AD. Christians, in a fit of religious fanaticism, destroyed everything that reminded of pagan culture. Only rewritten copies of Heron's works made by his students and followers have survived to our times. Some of them are in Greek, and some are in Arabic. There are also translations into Latin made in the 16th century. The most famous is Heron's "Metrics" - a scientific work that gives the definition of a spherical segment, a torus, rules and formulas for accurate and approximate calculation of the areas of regular polygons, the volumes of truncated cones and pyramids. The Metrics provides Heron's famous formula for determining the area of a triangle on three sides, and gives rules for the numerical solution of quadratic equations and the approximate extraction of square and cube roots. Metrics examines the simplest lifting devices - lever, block, wedge, inclined plane and screw, as well as some combinations of them. In this work, Heron introduces the term “simple machines” and uses the concept of moment of force to describe their work. Many mathematicians accuse Heron of the fact that the Metrics does not contain mathematical proofs of the conclusions he made. This is true. Heron was not a theorist; he preferred to explain all the formulas and rules he derived with clear practical examples. It is in the area of practice that Heron surpasses many of his predecessors.

The best illustration of this is his work "On the Diopter", found only in 1814. This work outlines methods for carrying out various geodetic works, and surveying is carried out using a device invented by Heron - a diopter.

Rice. 2.

Water through this tunnel was supplied to the city from a source located on the other side of Mount Castro. It was known that in order to speed up the work, the tunnel was dug simultaneously on both sides of the mountain, which required high qualifications from the engineer in charge of the construction. The water pipeline operated for many centuries and surprised Heron’s contemporaries; Herodotus also mentioned it in his writings. It was from Herodotus that the modern world learned about the existence of the Eupalina tunnel. I found out, but didn’t believe it, because it was believed that the ancient Greeks did not have the necessary technology to build such a complex object.

Having studied Heron’s work “On the Diopter”, found in 1814, scientists received the second documentary evidence of the existence of the tunnel. It was only at the end of the 19th century that a German archaeological expedition actually discovered the legendary Eupalina Tunnel. This is how in his work Heron gives an example of using the diopter he invented to build the Eupalina tunnel.

Fig.3.

Among other things, in the 34th chapter of the work “On the Diopter” Heron gives a description of the device he invented for measuring distances - the odometer.

The odometer was a small cart mounted on two wheels of specially selected diameter. The wheels turned exactly 400 times per millimeter (an ancient measure of length equal to 1598 m). Numerous wheels and axles were driven by gears, and the distance traveled was indicated by pebbles falling into a special tray. In order to find out how much distance was covered, all that was needed was to count the number of pebbles in the tray. The operation of the odometer is clearly demonstrated this video clip. One of Heron's most interesting works is "Pneumatics". The book contains descriptions of about 80 devices and mechanisms operating using the principles of pneumatics and hydraulics. The most famous device is the aeolipile (translated from Greek: “ball of the wind god Aeolus”).

The aeolipile was a tightly sealed cauldron with two pipes on the lid. A rotating hollow ball was installed on the tubes, on the surface of which two L-shaped nozzles were installed. Water was poured into the boiler through the hole, the hole was closed with a stopper, and the boiler was placed over the fire. The water boiled, steam was formed, which flowed through the tubes into the ball and into the L-shaped pipes. With sufficient pressure, jets of steam escaping from the nozzles quickly rotated the ball. Built by modern scientists according to Heron's drawings, the aeolipile developed up to 3500 revolutions per minute! When assembling the aeolipile, scientists encountered the problem of sealing in the hinge joints of the ball and steam supply tubes. With a large gap, the ball received a greater degree of freedom of rotation, but steam easily escaped through the gaps, and its pressure quickly dropped. If the gap was reduced, the loss of steam disappeared, but the ball also became more difficult to rotate due to increased friction.

We do not know how Heron solved this problem. Perhaps his aeolipile did not rotate at such a high speed as the modern model. Unfortunately, the aeolipile did not receive due recognition and was not in demand either in the era of antiquity or later, although it made a huge impression on everyone who saw it. This invention was treated only as a fun toy. In fact, Heron's aeolipile is the prototype of steam turbines, which appeared only two millennia later! Moreover, aeolipile can be considered one of the first jet engines. There was one step left before the discovery of the principle of jet propulsion: having an experimental setup in front of us, it was necessary to formulate the principle itself. Humanity spent almost 2000 years on this step. It is difficult to imagine what human history would have looked like if the principle of jet propulsion had become widespread 2000 years ago. Perhaps humanity would have long ago explored the entire solar system and reached the stars. I confess that sometimes the thought arises that the development of humanity has been deliberately delayed by someone or something for centuries. However, we will leave this topic for development by science fiction writers... It is interesting that the re-invention of Heron’s aeolipile took place in 1750.

Hungarian scientist J.A. Segner built a prototype of a hydraulic turbine. The difference between the so-called Segner wheel and the aeolipile is that the reactive force rotating the device is created not by steam, but by a jet of liquid. Currently, the invention of the Hungarian scientist serves as a classic demonstration of jet propulsion in physics courses, and in fields and parks it is used to water plants. Another outstanding invention of Heron related to the use of steam is the steam boiler.