Antiquity knew the elements of automation, the driving force of steam. The inventive genius of man, which has demonstrated its strength since primitive times, has not dried up. A striking example of this is the technical creativity of Heron of Alexandria, who lived approximately 120 years BC. e. Heron's teacher, Ctesibius of Alexandria, whom the historian of ancient science and technology Diels calls the head of ancient engineers, invented an air organ, a fire engine, and an automatic water clock (clepsydra). In the clepsydra of Ctesibius, water from water supply A enters the regulating tank BCDE and falls through a narrow tube E into the tank KLMN. With strong pressure, water does not have time to drain through E, accumulates in the control tank and raises the float G, which blocks the access of water. In this way, a certain normal level is maintained in the control tank as long as the tap F is open. Flowing into the tank, water raises the float P, on which stands a figure showing with a stick a clock marked in the form of horizontal lines on a rotating STUV drum (see Fig. 14 ).
Ctesibius Heroes describes the fire engine as follows:
“Fire pumps used to extinguish fires are made as follows (Fig. 15): two metal cylinders are drilled from the inside with a lathe cutter according to the size of the piston, just as a craftsman drills out “pumps” for wells. KL and MN are precisely fitted pistons. The cylinders are connected to each other by an XODE pipe and are equipped from the outside (inside the XODE pipe) with valves P and R that open outward. The bottom of the cylinders has 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 Z a) is connected to them, which rotates in the middle around a bolt δ; the piston rods S rotate around bolts b and v. Above the hole in the XODE tube, another vertical fork-shaped tube ξ is installed, equipped with a faucet-like nozzle, through which water is ejected in the same way as we already said above when describing the vessel that ejected water using air compressed in it.”
The valve mentioned in this description (Fig. 16) 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 records be ABCD and EFGH. In one of them, namely ABCD, a round hole one-third of a finger wide was drilled. The edge of the CD is connected by a hinge to the edge of the FE, so that the ground sides of the metal plates rest on one another. When they want to use these valves, the ABCD plate is tightly soldered to the hole through which air or water must enter. In this case, under pressure from the inside, the EFGH plate opens and allows air or water to pass through. But then the air or water pressure will force the EFGH plate against the hole through which the 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 is just 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 cups): the skin of the finger covering the hole of the vessel will be retracted. inside. 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.
Let's immerse the elbow tube АHDBCKL (Fig. 17) in a vessel filled with water to level FG. The water in the elbow will reach the H 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 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 rupture of the jet, c) the outweighing 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.
Heron, however, sees the insufficiency of his explanation of the action of the siphon. 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 a center at the center of the Earth. Consequently, the liquid will flow with top level to a lower one until the levels are equal. We see that Heron, starting from Archimedes, essentially formulates the principle of communicating vessels. 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, the ball is immersed in liquid, then the liquid will enter through the hole 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. 18) is a tube, closed at the top, but open at the bottom. Inside this tube is placed a second one, 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 top. 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. 19), 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. 20). 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 owl bucket will empty and 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 “eolipile”. Heron's aeolipile is an iron ball that can rotate around a horizontal axis (Fig. 21). 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 take as an example of the use of the driving force of heat an altar with automatically opening doors when a sacrificial fire is lit (Fig. 22).
In the temple there is a hollow altar DE, which is connected through a tube FG by a spherical vessel PH, half filled with water. A KLM U-shaped tube 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 weight 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 XN, which, being empty, is lighter than the load. One of the elbows of a U-shaped tube passes into this vessel, which is installed in such a way that when the doors are closed, this elbow reaches 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 resurgent new science turned to Heron's inventions, developing them further on a new basis.
But this science, having preserved the description of the aeolipile in physics textbooks, did not begin to build a steam engine according to Heron’s principle, but implemented the less perfect idea of a steam-atmospheric pump. Heron's inventions were clear evidence that ancient science moved from considering general problems to specific ones. Astronomy, mathematics, mechanics, geography, and medicine began to stand out from a single science. The center of the new science was the city founded by Alexander the Great in the Nile Delta - Alexandria. A unique scientific institution arose here - the Alexandria Museum with a rich library and an astronomical observatory. All major scientists and philosophers ancient world to one degree or another connected with Alexandria. Therefore, the period of the separation of sciences is often called the Alexandrian period.
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 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 almost modern look. 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 the width of a finger. The edge of the CD is connected by a hinge to the edge of the FE, so that the ground sides of the metal plates lie on top of each other. When one wants to use these valves, the plate ABCD. soldered tightly to the hole through which air or water must enter. In this case, when the 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 the 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 weight 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 weight B. 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.
Ancient Greek cultural heritage so great that we may still not know something about their great achievements. This state gave us philosophy, as well as direct democracy, mathematics and the foundations of empirical physics, but even now the classical stage of the history of the development of this state continues to surprise us. The reader of this article thinks that we live in an era of mechanics and robotization, but this article will completely change his idea of the Ancient World, because 2000 years ago there lived one Greek who not only dreamed of machines, he created them. It was the Greeks who started the first machine age...
List of inventions:
We have admired the world for centuries Ancient Greece, where the mind could rise above everyday life in search of the great. The heyday of science, art and philosophy, bright ideas that would then sweep the whole world. At the center of this age of wonder lay not Italy or Greece, but a city in the north Ancient Egypt- Alexandria. While the Romans were absorbed in wars, and the Greeks were dreaming of philosophy, in Alexandria they were thinking about thought itself. Here one could find a not very famous Greek, such as Plato or Aristotle, he was an inventor. He almost started the industrial revolution 2 thousand years ago. Contemporaries called him “mekanikos”, and we know him as, and we will tell you everything about Heron in this article.
Now we live in the industrial age, we are surrounded by various machines and mechanisms. Perhaps future generations will say that it was we who marked the beginning of the machine age, because cars, airplanes, computers and robots appeared. But we are not the first to dream of everyday worries being solved with the help of machines. Aristotle thought about this, he imagined a world where looms would be automatic, harps would play the melody themselves, craftsmen would not need assistants and there would be no need to keep slaves, why is this not a copy of the modern world? But Heron went even further. He didn't just dream about cars, he built them!
Heron of Alexandria. A modern sketch.
Two thousand years ago, Heron ushered in the era of mechanization, creating machines that still blow our minds. Heron lived in Alexandria at a time when this city was the most multinational in the world. This wonderful place, where the irresistible Queen Cleopatra once lived, has concentrated all knowledge in its depths classical world. Great minds came here to trade the most valuable of wealth - not gold, not slaves, not silver, but knowledge. Two thousand years ago it was the center of world science. The bank of this knowledge was the great library. The works of the Greeks, Egyptians and other peoples were collected here. The scrolls were filled with fables, poems, and the works of mathematicians and philosophers. It was there that all of Heron's inventions were kept. Not a single one of his machines has survived to this day, and we know almost nothing about the inventor himself, but we have ideas about his wonderful creations, because descriptions of these machines have come to us in the form of copies of those scrolls that Heron wrote. They open a window into his magical mechanized world. Thus, one of the copies of the books, which describes the works of the great inventor, has been preserved at Oxford University. Among his inventions there are those that were intended for the home, while others were used as entertainment at dinner parties, some produced special effects in the theater (ringing, buzzing, whistling, creating animal sounds, etc.), but most often Heron's machines could not be found in these places, but in temples.
Alexandria gathered under its wing so many religions and cults like no other city in the ancient world, and competition grew among them. Today the city's main religion is Islam, but in ancient times there was a much wider choice. The temples of ancient Alexandria offered patronage and support to a host of strange and archaic gods. The ancient Egyptian deities, which had been worshiped for over three thousand years, were still revered by many Egyptians and some visitors. Even the Greeks were afraid of angering gods such as Isis and Osiris, who had guarded the temple since the time of the pharaohs. Along with the Egyptian religions, the religions of the Romans and Greeks coexisted, as well as numerous cults from the outskirts of the Roman Empire. Everyone needed followers and money, so something special was needed to attract attention to a particular temple. Possessing something unusual became an advantage in the competition of religions and cults. In other words, all priests needed magic, and Heron could provide it.
Automatic doors
Heron called his “magic” mechanism “machine No. 37,” and we would call it “automatic doors.” The idea was brilliant, albeit simple. When the priest and parishioners approached the temple, the doors magically opened to let them in. How did this happen? First, the priest lit a fire on a special sacrificial altar in front of the huge closed gates of the temple. Under the altar, underground, there were many pipes and containers, as well as scales. Invisible to the eyes of the congregation, they began their work. The buckets that served as a counterweight were filled with water. Meanwhile, the priest could make various ritual offerings, and the heat of the fire would activate hidden mechanisms. Then, when the scales are full, the doors slowly open, giving the impression that the gods are pleased with the offerings. If the gates did not open due to some malfunction, then we can always say that the gods were disappointed with the gifts of the parishioners. The fantastic ending in the form of the doors opening was accompanied by the sound of a fanfare. This is a special mechanism that, under pressure, expelled air through a pipe. For Heron it was mechanics, but for ordinary person- miracle.
The physical meaning is quite simple. A lit fire increased the pressure in a large vessel (the air heated up), due to which water from it began to move under pressure into the bucket. The bucket increased in weight and, using the principle of a counterweight, lifted a weight on the opposite side through a system of ropes. The ropes were simply twisted around two rotating pillars. When the fire went out, the pressure returned to normal, and the water from the bucket returned back to the common tank, and the gate closed.
There is a point of view that this temple could have been equipped with such doors.
Vending machine
Of course, it’s one thing to convince people to come to your temple, but it’s a completely different thing to part with their money, and it was money that was the basis of a successful religion. How to get parishioners to spend them and how to collect them? These were the questions Heron asked himself. And he managed to answer them. The first solution is a holy water dispenser. It was the world's first vending machine.
Those entering the temple had to wash their hands with water blessed by the priests. However, lighting the water and selling it took a lot of time, so Heron optimized these processes. The parishioner threw one drachma into a special container through a coin slot and received his cup of water. For believers, this was another miracle, but in reality the coin simply fell onto a special platform, which opened the water valve for a while.
To those who could see everything from the inside, it seemed like another masterpiece of mechanics. It turns out that Heron invented the vending machine 1800 years before its modern equivalent was patented.
Portable fire extinguishing pump
Heron's experiments with water and pressure may have led him to create the first portable pump for extinguishing fires.
The pump consisted of two communicating piston cylinders, inside of which there were valves. The water was pushed out in turn, first from one cylinder, then from the other. To operate the pump, two people were required, who, using the lever principle, started the pump. Later, the Romans widely used such pumps to extinguish fires in cities. True, they improved the technology itself, making parts very precisely, trying to fit everything perfectly. Such hand pumps were used for a very long time in Europe, until electricity was invented. With its help it was possible not only to extinguish the fire, but also to pump out water from the holds of ships.
The principle of operation of the pump can be seen in this video:
Turning water into wine
It is likely that the following two inventions were also used in temples. Both of them are vessels with wine and water.
The first invention consists of two vessels, where water is poured into one, and wine into the second. They are connected to each other by a tube. Believers poured a small amount of water into the first vessel, and wine flowed from the second. All this was presented as the magic of turning water into wine. In fact, we see a principle that is taught in 7th grade physics class - communicating vessels.
The next invention also turned water into wine, but did it in a different way. It was a special amphora, one half of which was filled with wine and the other with water. Naturally, there was a special partition between them, which divided the amphora into two parts. The top of the amphora had two holes just below the handles. One hole for each compartment. The priest brought the goblet to the amphora and, quietly plugging one of the holes, poured either water or wine. All this was then presented as the will of the gods! Was it true that everything was simpler when there were gods? 🙂
Fountain of Heron scheme
What is Heron's Fountain? The Eternal Fountain of Heron consists of three vessels, which are placed one above the other and communicate with each other using tubes. The two lower vessels are closed, and the upper one has the shape of a bowl, where the visible part of the processes from the observer takes place. Here everything is also based on the principles of potential energy, gravity, pressure and communicating vessels.
It is also explained in sufficient detail how Heron's fountain works in this video:
Music box of predictions
Heron came up with another money-collecting machine for the priests. She made the parishioners believe that they were talking to the gods, but this was just another trick. This is a prediction mechanism. One of the reasons why people went to the temple was to find out their future, and ancient people (although now also) were willing to pay for this pleasure. The parishioners, of course, did not see the mechanism, since the machine itself stood in twilight. All that was visible was a wheel, a house and a singing bird. Once payment is made, God can be asked a question that can be answered “yes” or “no.” As the bird turned the wheel, it either sang or remained silent. The priests explained everything in such a way that people believed that God was answering them. Of course, the bird sang not by God's will, but by the will of Heron. Inside were many gears and ropes that made the bird sing when the wheel was turned. There was also a special protrusion attached from the inside that could be released. Most likely, this was necessary so that the priests could control the answers to questions, that is, so that the bird would remain silent. Bird singing - yes, silence - no, and the priestesses could choose the desired answer. This is one of the oldest religious tricks in the world. The beautiful singing of the bird was just a whistle that was lowered into a container of water.
Sounds were an integral attribute of all of Heron's inventions, from the prediction machine to the complex wind organs. However, getting them to work together is much more difficult than it might seem. The birdsong mechanism uses the principle of a siphon, yes, the same one that is used in toilets and other plumbing systems. Water is poured from above, and when it reaches a certain point, it pours out at high speed. This flow pushes air out of the pipes, which is why the whistle begins to play a given sound, and the hole with the bird’s beak opens and closes.
Heron built and enough complex machines. In this entertainment device, when you pick up an apple, the figure of Hercules shoots a bow at the dragon. This is one of his exploits - Apples of the Hesperides. Hercules needed to kill the dragon who was guarding the garden with apples that bestow immortality.
The entire structure consists of the upper visible part and inner part with two cavities connected through a hole initially plugged with a plug. The cork is connected to the apple, and the arrow is also launched through this rope. As soon as the apple is lifted, water from the upper container pours into the lower one, while pushing air through a special tube, creating the hiss of a dragon dying from death.
Polybolos
Prediction machines were especially successful during wars, because everyone wanted to know the outcome of the war, to find out whether he and his loved ones would survive. However, Heron could give more than a simple prediction. He came up with not only something that could predict the outcome of the war, but also help win the war. We are talking about Heron's war machines. He turned his attention to the art of warfare, he decided to automate war. Deadly war machines were much more fearless than the soldiers of those times and much more militant. This technology was centuries ahead of its time - the polybolos, the first automatic weapon. This crossbow has many unique abilities: it was the first to use a chain mechanism; it could shoot further and more accurately than any man; the main thing is that it was automatic and fired one arrow after another, without requiring rest.
The Roman army was interested in such weapons, since their use provided great advantages. Taking into account the length of the empire’s border, these weapons made it possible to successfully defend borders and equip forts.
Heron's Automatic Hand Crossbow
This car comes from Alexandria. There is reason to believe that Heron of Alexandria also invented it. The device replicates the actions of a traditional archer, but fires an arrow with greater power. This is essentially a military robot. The long part of the machine copies the outstretched arm of an archer. The double lever system allows you to pull the bowstring, sandwiched between two metal hooks, to a strong tension that cannot be produced by hand.
Automatic mobile scenery of Heron
But Heron had more to offer Alexandria than war machines and magical machines. He wanted to entertain and chose for this a place where everything is possible - the theater!
In ancient times, the theater was the center of many people's lives. Here people communicated and exchanged news, and also enriched themselves culturally and religiously. This is essentially the ancient equivalent of cinema - a dream world. There was amazing acoustics here, which made what was happening on stage closer and more real.
Heron knew that he could give a lot to the theater. The knowledge acquired during the creation of military vehicles and toys for temples could find its application in the theater. His decorations could appear on stage and disappear when necessary.
The compartment at the top of the mechanism was filled with sand, and when it poured out through a series of holes, it lowered the scales. The bowl was attached to a rope that was wound around the shaft. When the rope unwound, the device moved forward. Then, by switching the lever, the load was lifted and the structure rolled away.
Heron wrote a whole treatise on automatic theaters. The meaning of such a theater is that it moves on its own. From Greek, “automatic” is translated as movement in itself. At the same time, Heron tried to make the mechanisms small so that people would not think that there was a person inside who controlled everything.
A simple axle with wooden nails that produced all these movements may have been greatest invention Gerona. A modern scientist would call this programming. It is not surprising that theater visitors admired these decorations.
Automatic Theater of Heron
Heron automated the sets, but what about the actors? He created a fully automatic theater with movable sets, automatic actors and special effects. 20 minutes of fun! Heron began with a classic Greek story of bloody revenge. It tells how King Naplius seeks revenge on his son, who was killed by Ajax during the Trojan War. The play begins with 12 characters building a warship, all without human intervention. Below, hidden from the viewer's eyes, is the mechanism itself. The spectators were shocked by the fact that all 12 figures moved synchronously. To complete the picture, Heron added sounds and special effects. The scenery and characters changed, the curtain automatically rose and fell. To prevent collisions between the actors, they were located in different planes, which appeared and disappeared during the performance.
This whole action was driven by weights and ropes, as well as containers with sand and grain. The required energy was produced using gravity. Such a number of automated elements was a real feat of genius!
When it was necessary to create the sound of thunder when a ship was caught in a storm, Heron launched his thunder installation to slightly scare and excite the audience. These were heavy metal balls that rolled and fell on special platforms, eventually landing on a large drum.
In the midst of events, the goddess Athena appears, who controls the weather. Ajax is struck by lightning, and the hero Naplius returns home.
One can only guess how the ancient Greeks admired this. After all, it looked simply amazing. In fact they are simply brilliant mathematical calculations for that time, because it was necessary to calculate the time of each scene, the balance of ropes and weights, the speed of gears and sand, the sequence of appearance characters. This would puzzle even modern engineers. We can safely call the Heron Theater a wooden programmable robotic controller.
If any of you studied at the Faculty of Construction or Forestry Engineering, then you were required to be taught how to use a theodolite, which is so necessary for geodesy. But this instrument was also invented by Heron! He called his device dipotra.
The main component of the diopter is a ruler that rotates in a circle and allows you to mark the horizontal and vertical positions. A plumb line and level were also attached to the device. Using these tools, as well as mathematical techniques and rectangular coordinates, Heron was able to solve many construction problems:
- measured the distance between two points when one or even both are not within sight;
- drew a straight line, perpendicular to another line, which was inaccessible to the eye;
- found level differences between two points;
- measured areas without even going to the place he was measuring.
The water supply system on the island of Samos was considered one of the wonders of engineering in the time of Heron. The design of this water pipeline was invented by Eupalinus. This project brought water to the city from the Mount Castro spring. To speed up the work, it was decided to dig a tunnel from both sides at once, but the problem is how can the workers definitely not miss and connect at one point? This project required enormous engineering competence. Nevertheless, the water supply system was built and surprised Heron’s contemporaries for a long time. Herodotus also mentioned this miraculous water pipeline, thanks to whom the world generally learned about the existence of the Eupalina tunnel. True, no one believed for a long time that this was true. It was believed that the ancient Greeks did not have sufficient technology to build such complex objects, but in 1814, having studied the works of Heron on the diopter and the construction of the Eupalina tunnel with its help, doubts came to naught, and at the end of the 19th century the tunnel itself was found.
Heron's odometer
In his work “On the Diopter,” the inventor also outlined the principles of a device that allows you to measure distance—the odometer.
Outwardly, it was a small cart with two wheels of a certain diameter. If you turn the wheels 400 times, it will be equal to 1598 meters (the ancient Greek measure of length is equal to one milliatre). The odometer diagram is shown in the figure, where we see that the various wheels and axles rotated using a gear drive. The pebbles that fell onto a special platform indicated the distance traveled. When the cart passed, the person measuring the distance only needed to count the stones.
And here is another wonderful invention of Heron of Alexandria - a steam boiler. The Greeks also loved to wash :)
The steam boiler was a bronze container placed in a special cylinder so that the boiler and the cylinder had a common axis. There was a brazier at the top. There were also pipes through which cold water, as well as a pipe for output hot water. Such a simple design was quite economical and made it possible to quickly heat up the water.
Heron steam jet turbine
This invention of Heron of Alexandria was capable of laying the foundation for a scientific and technological revolution, but, unfortunately, it did not find proper application. We are talking about the ancestor of the steam engine - aeolipile. Heron was close to inventing the steam engine.
Aeolipile was designed as follows. Water was poured into the lower container. Then a fire was lit. The water rose through the tubes (steam pipelines) and came out in the form of steam, and at the same time set in motion the ball itself, which rotated at a frantic speed for that time.
To this ball it was necessary to add knowledge about pistons and the steam engine would be ready. As it was, the aeolipile did not set anything in motion except itself, so it remained just a funny artifact that could be used to entertain guests.
Theoretical achievements of Heron
Of course, seeing all this variety of machines, you can immediately guess that Heron also left a lot of theoretical calculations. Thus, his most famous works are “Pneumatics” and “Mechanics”, where he systematically outlined many of the achievements of ancient science in the field of mathematics and applied mechanics. He also, as mentioned above, wrote a whole book about automated theaters, “The Theater of Automata.” Heron also discovered formulas for determining the areas and volumes of certain geometric shapes., which was reflected in his work “Metrics”. One of his most famous formulas allows one to find the area of a triangle based on its three sides, and Heron’s formula was named after him. .
Excerpt from “About the Diopter”
Of particular interest is his work “On the Diopter,” which was discovered only in 1814. In this book, he outlined the principles of a modern geodetic instrument - the theodolite, as well as the rules of land surveying.
Heron wrote a treatise “On the Making of Throwing Machines,” where he spoke about the fundamental aspects of artillery in antiquity.
This genius even studied the properties of mirrors. In his scientific work “Catoprtrika”, he provided a rationale for the law of reflection, and also studied the straightness of light rays.
Basically, his works are descriptive in nature, outlining certain principles. It is unlikely that all works claim some kind of integrity, and in works on mathematics you may not even find evidence. Here Heron’s empiricism is manifested and the practitioner outplays the theorist.
Heron is like Tony Stark, only real and straight from Ancient Greece.
Living in a modern high-tech society, we are very proud of the inventions of our time, the development of technology, these main characteristics, " business cards", as we believe, our civilization.
However, it is worth looking back at least two thousand years, and we will be surprised to discover that our inventions are not so ours. Something similar, it turns out, had already been invented and was even quite successfully used. And we are not talking about paleocontacts or “gifts of the gods”; most likely, these are ordinary, although far from ordinary, fruits of human engineering.
Many of these engineering gems were simply far ahead of their time, and this is the only way I can personally explain how they, despite their usefulness, could be forgotten by humanity, and even so much so that they subsequently received a second life. This is exactly what happened with the very first steam engine.
Heron Alexandrinus, or Heron of Alexandria, was born in 10 AD in Alexandria (now part of Egypt and the second largest city after Cairo). There is little information about Heron's life, however, it is known that his parents were Greeks who moved to Alexandria after its conquest by Alexander the Great. Heron was a mathematician and inventor, one of the greatest inventors of antiquity.
During the era of Heron, the great Library of Alexandria was in its heyday and, according to scientists, Heron had the opportunity to use this repository of human wisdom, knowledge and experience.
Aeolipile - Heron's sphere
In fact, few people know that Heron was also the inventor of the first steam engine, a device that was called the aeolipile or “Heron's engine” or “Heron's ball”.
Although some researchers believe that there were devices similar to the aeolipile before Heron, he was the first to describe its design and manufacturing method in detail in his book “Pneumatics,” where in addition 78 more devices were described. Many of Heron's ideas were improvements on another Greek inventor who lived in Alexandria 300 years before him, one Ctesibius of Alexandria, who first mentioned the science of compressed air.
So what was this same aeolipile, the most ancient steam engine, like? This is a sphere capable of rotating around its axis. The sphere moved thanks to steam ejected under pressure from a pair of nozzles. The nozzles were directed in opposite directions, resulting in a torque. It was this torque that caused the sphere to spin around its axis. The operating principle is shown in the video at the end of this article.
The steam was generated by boiling water either inside or below the sphere, as in the figure. If the boiler is located under the sphere, then it is connected to it using a pair of pipes, which simultaneously serve as axes for it. A reproduced modern copy of Heron's steam engine is capable of accelerating to 1,500 rpm at a relatively low pressure of 0.7 kg per square inch.
This invention was undeservedly forgotten until 1577, when the steam engine was reinvented by the philosopher, astronomer and inventor Taqi Al-Din. The principle of operation of the device he described basically repeated the principle of the steam engine of Heron of Alexandria, with the exception that the steam flows set the wheel in motion.
Another invention attributed to Heron, and in fact, which was his improvement of the hydraulic device already invented by Ctesibius, was the “wind wheel”. It was a wind turbine that was used to operate a device similar to a modern organ.
Heron also invented the very first vending machine for selling holy water, automatic door opening, a fire engine, an autonomous fountain and many mechanisms for the Greek theater.
One of his theatrical mechanical inventions was a completely mechanized theatrical play. She worked, without going into technical details, using a system of knots and ropes and simple mechanisms, and was even capable of artificially creating the sounds of thunder and controlling the light during the performance.
His legacy describes machines powered by air, steam or water under pressure, architectural devices for lifting heavy objects, methods for calculating surfaces and quantities (including a method for calculating the square root), military mechanisms, as well as methods for controlling light using reflectors and mirrors
“Wonderful” door opening. Heron's invention. Animated images by P. Hausladen, RS. Vöhringen
Definitely, Heron was a genius for his time, an incredibly progressive person. Unfortunately, most of his original writings have been lost, with the exception of a few surviving Arabic manuscripts. Who knows how many more incredible, now forgotten inventions of the ancient world were described by Heron more than 2000 years ago.
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 even use special term: “chronoclasms” are 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 brought in his time huge contribution in the development of science, 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 - treatise, which provides a definition of a spherical segment, a torus, rules and formulas for accurate and approximate calculation of the areas of regular polygons, volumes of truncated cones and pyramids. In "Metrics" the famous Heron formula is given for determining the area of a triangle on three sides, and the rules for numerical solution are given quadratic equations and 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 theoretician, he preferred all the formulas and rules he derived explain 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.
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 area simplest figure, without even entering the measured area. 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. Precisely from Herodotus 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 necessary technology for the construction of such a complex object.
Having studied Heron’s work “On the Diopter”, found in 1814, scientists received the second documentary confirmation existence of the tunnel. And only in late XIX century, 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.
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 angle b 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.
The odometer was a small cart mounted on two wheels of specially selected diameter. The wheels turned exactly 400 times per milliatri (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 the most interesting works Gerona 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 greater degree freedom of rotation, but steam easily escaped through the cracks, 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 a prototype 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 studied all 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 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.
