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In our society today we are often surprised and impressed by the advancement of technology and engineering, a major characteristic of our civilisation. However if we look back more than 2,000 years ago, we can find mechanical marvels and incredible feats of engineering that were ahead of their time. Many became lost to the pages of history, only to become reinvented just a few centuries ago. This includes the first modern of the steam engine.
Heron Alexandrinus, or Hero of Alexandria as he was often known, was a Greek born in 10AD in Alexandria, now part of Egypt, and the second largest city after Cairo. Little is known about the life of Heron, however, we are aware that he was born to Greek parents that migrated to Alexandria after the conquest of Alexander the Great. Heron was a mathematician and an engineer considered to be one of the greatest inventors of ancient times.
During the era in which Heron lived, the great Library of Alexandria was in its glory and Heron is believed to have taught at the Museum of Alexandria, a place for scientists and scholars to meet and discuss.
What very few people know, thanks to the omission of important facts from our history books, is that Heron was the first inventor of the steam engine , a steam powered device that was called aeolipile or the ‘Heron engine’. The name comes from the greek word ‘Aiolos’ who was the Greek God of the winds.
Although a few others have talked about devices similar to aeolipiles before Heron, Heron was the first one to describe them in detail and give instructions for manufacturing them in his book Pneumatica, where more than 78 devices are described. Many of Heron’s ideas were extensions and improvements of another Greek inventor who lived in Alexandria 300 years before him, known as Ktesibios, the first to write about the science of compressed air.
But what is an aeolipile? It is a sphere that is positioned in such a way that it can rotate around its axis. Nozzles that are opposite to each other would expel steam and both of the nozzles would generate a combined thrust resulting in torque, causing the sphere to spin around its axis. The rotation force speeds up the sphere up to the point where the resistance from traction and air brings it to a stable rotation speed. The second video at the end of this article demonstrates how it works.
The steam was created by boiling water either inside the sphere or under it, as seen in the image. If the boiler is under the sphere, then it is connected to the rotating sphere through a pair of pipes that at the same time serve as pivots for the sphere. The replica of Heron’s machine could rotate at 1,500 rounds per minute with a very low pressure of 1.8 pounds per square inch.
PLACE a cauldron over a fire: a ball shall revolve on a pivot. A fire is lighted under a cauldron, A B, (fig. 50), containing water, and covered at the mouth by the lid C D; with this the bent tube E F G communicates, the extremity of the tube being fitted into a hollow ball, H K. Opposite to the extremity G place a pivot, L M, resting on the lid C D; and let the ball contain two bent pipes, communicating with it at the opposite extremities of a diameter, and bent in opposite directions, the bends being at right angles and across the lines F G, L M. As the cauldron gets hot it will be found that the steam, entering the ball through E F G, passes out through the bent tubes towards the lid, and causes the ball to revolve, as in the case of the dancing figures.
This invention was forgotten and never used properly until 1577, when the steam engine was re-invented by the philosopher, astronomer and engineer, Taqu al-Din. But he basically described the same device as Heron, a method for rotating a spit by using jets streams on the periphery of a wheel.
Reconstruction of one of many “automata” of Heron ( Source)
Another invention of Heron was the ‘wind wheel’, a wind-driven wheel that was used to power a machine that was connected to a pipe organ. He also invented the first vending machine, automatic opening doors, ‘ miraculous’ movements and sounds in temples, a fire engine, a standalone fountain, and many of the mechanisms of the Greek theatre. One of his theatrical mechanical inventions included a completely mechanical robotic theatrical play by using a binary system of knots and ropes and simple machines, even creating artificial sounds of thunder, pumps and concentration of light to specific parts of the performance. His works include descriptions of machines working on air, steam or water pressure, architectural devices for lifting heavy objects, methods of calculating surfaces and volumes – including a method of calculating the square root, war machines, and manipulation of light using reflection and mirrors.
Animated Image by P. Hausladen, RS Vöhringen
It is clear that Heron was a genius with knowledge that was incredibly advanced for the time. Unfortunately, most of his original writings have been lost, with just a few surviving in Arabic Manuscripts. Who knows how many more incredible inventions were documented by Heron more than 2,000 years ago.
Pneumatica – Hero of Alexandria
How Do Steam Engines Work?
Donning Kindersley / Getty Images
Heat water to its boiling point and it changes from being a liquid to become the gas or water vapor we know as steam. When water becomes steam its volume increases about 1,600 times, that expansion is full of energy.
An engine is a machine that converts energy into mechanical force or motion that can turn pistons and wheels. The purpose of an engine is to provide power, a steam engine provides mechanical power by using the energy of steam.
Steam engines were the first successful engines invented and were the driving force behind the industrial revolution. They have been used to power the first trains, ships, factories, and even cars. And while steam engines were definitely important in the past, they also now have a new future in supplying us with power with geothermal energy sources.
The child of practice and theory
The classical era was after all a time of great ideas. Democritus famously taught the world was made by atoms. Aristarchus, though losing the popular debate for many centuries, believed the sun was the center of the solar system. The geometry you learned in school was almost completely elaborated by Euclid — many modern textbooks even follow the same format and use the same examples as his Elements. Eratosthenes measured the size of the Earth to great precision.
Technology also advanced in many key areas. The steam engine, so instrumental to the explosion of technological and economic progress during the industrial revolution, was in many ways tantalizingly close to being realized.
There is the actual first recorded steam engine in history, Hero of Alexandria’s Aeolipile. Widely published and noted in the Roman world, this device demonstrated that steam could be used to convert heat into work. There is little evidence of it actually being used for practical purposes, however. It continued to be seen as a technological wonder for amusement, much like magnetism centuries later.
There are certainly technological hurdles between Hero’s apparatus and the early working steam engines of Henry Newcomen (1712) and James Watt (1774), which brings us to the status of engineering in the Roman world. What we today call engineers, and the Romans called architects, enjoyed a high status in their world. The army, obviously, greatly benefited from siege engines, roads and bridges. The growing cities depended on aqueducts to transport the population’s increasing need for water over unprecedented distances. Improved mining, buildings, roads and the world’s first indoor sanitation systems were all prerequisites for meeting the needs of the empire.
Vitrivius was perhaps the most famous of his days’ architects (read: civil engineers), and he expressed his ideal in a way that sounds tantalizingly modern:
“The architect should be equipped with knowledge of many branches of study and varied kinds of learning, for it is by his judgement that all work done by the other arts is put to test. This knowledge is the child of practice and theory.”
Even up to modern times, theorists were often reluctant to be involved in practical applications of their work. Joseph Henry, the noted 19th century American scientist, contributed greatly to our understanding of electricity. He was certainly not unable to find practical applications of his knowledge — he made the world’s first electric doorbell, with a mile-long wire, to alert his wife when he would be home for dinner. Yet it fell to inventors like Samuel Morse to bring out a practical application that literally would change the world. Vitrivius, in the 1st century, strived to unite practice and theory, crafts and philosophy.
Heron of Alexandria
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Heron of Alexandria, also called Hero, (flourished c. ad 62, Alexandria, Egypt), Greek geometer and inventor whose writings preserved for posterity a knowledge of the mathematics and engineering of Babylonia, ancient Egypt, and the Greco-Roman world.
Heron’s most important geometric work, Metrica, was lost until 1896. It is a compendium, in three books, of geometric rules and formulas that Heron gathered from a variety of sources, some of them going back to ancient Babylon, on areas and volumes of plane and solid figures. Book I enumerates means of finding the area of various plane figures and the surface areas of common solids. Included is a derivation of Heron’s formula (actually, Archimedes’ formula) for the area A of a triangle, A = Square root of √ s(s−a)(s−b)(s−c) in which a, b, and c are the lengths of the sides of the triangle, and s is one-half the triangle’s perimeter. Book I also contains an iterative method known by the Babylonians (c. 2000 bc ) for approximating the square root of a number to arbitrary accuracy. (A variation on such an iterative method is frequently employed by computers today.) Book II gives methods for computing volumes of various solids, including the five regular Platonic solids. Book III treats the division of various plane and solid figures into parts according to some given ratio.
Other works on geometry ascribed to Heron are Geometrica, Stereometrica, Mensurae, Geodaesia, Definitiones, and Liber Geëponicus, which contain problems similar to those in the Metrica. However, the first three are certainly not by Heron in their present form, and the sixth consists largely of extracts from the first. Akin to these works is the Dioptra, a book on land surveying it contains a description of the diopter, a surveying instrument used for the same purposes as the modern theodolite. The treatise also contains applications of the diopter to measuring celestial distances and describes a method for finding the distance between Alexandria and Rome from the difference between local times at which a lunar eclipse would be observed at the two cities. It ends with the description of an odometer for measuring the distance a wagon or cart travels. Catoptrica (“Reflection”) exists only as a Latin translation of a work formerly thought to be a fragment of Ptolemy’s Optica. In Catoptrica Heron explains the rectilinear propagation of light and the law of reflection.
Of Heron’s writings on mechanics, all that remain in Greek are Pneumatica, Automatopoietica, Belopoeica, and Cheirobalistra. The Pneumatica, in two books, describes a menagerie of mechanical devices, or “toys”: singing birds, puppets, coin-operated machines, a fire engine, a water organ, and his most famous invention, the aeolipile, the first steam-powered engine. This last device consists of a sphere mounted on a boiler by an axial shaft with two canted nozzles that produce a rotary motion as steam escapes. (See the animation .) The Belopoeica (“Engines of War”) purports to be based on a work by Ctesibius of Alexandria (fl. c. 270 bc ). Heron’s Mechanica, in three books, survives only in an Arabic translation, somewhat altered. This work is cited by Pappus of Alexandria (fl. ad 300), as is also the Baroulcus (“Methods of Lifting Heavy Weights”). Mechanica, which is closely based on the work of Archimedes, presents a wide range of engineering principles, including a theory of motion, a theory of the balance, methods of lifting and transporting heavy objects with mechanical devices, and how to calculate the centre of gravity for various simple shapes. Both Belopoeica and Mechanica contain Heron’s solution of the problem of two mean proportionals—two quantities, x and y, that satisfy the ratios a:x = x:y = y:b, in which a and b are known—which can be used to solve the problem of constructing a cube with double the volume of a given cube. (For the discovery of the mean proportional relationship see Hippocrates of Chios.)
Only fragments of other treatises by Heron remain. One on water clocks is referred to by Pappus and the philosopher Proclus ( ad 410–485). Another, a commentary on Euclid’s Elements, is often quoted in a surviving Arabic work by Abu’l-‘Abbās al-Faḍl ibn Ḥātim al-Nayrīzī (c. 865–922).
Powering the Industrial Revolution
But by 1765, the fate of Newcomen's engine was sealed. In that year, James Watt, a Scottish instrument maker employed by Glasgow University, began repairing a small model of a Newcomen engine. Watt was perplexed by the large amount of steam consumed by Newcomen's machine and realized that to remedy this inefficiency, he would have to do away with the constant cooling and reheating of the steam cylinder.
To do this, Watt developed a separate condenser, which allowed the steam cylinder to be maintained at a constant temperature and dramatically improved the functionality of Newcomen's engine.
For financial reasons, Watt wasn't immediately able to manufacture his new and improved atmospheric engine. But by 1776, he had formed a partnership with Matthew Boulton, an English manufacturer and engineer dead-set on using steam engines for more than just pumping water from mines.
With financial backing from Boulton, Watt developed a single-acting (and later, a double-acting) rotative steam engine that, along with Watt's signature separate condenser, featured a parallel motion mechanism that doubled the power of the existing steam cylinder. The Boulton-Watt engine was also the first that allowed the machine's operator to control the engine speed with a device called a centrifugal governor. The improved engine used a new gear system &mdash developed by Boulton and Watts' employee, William Murdoch &mdash known as sun and planet gearing, to convert reciprocating (linear) motion into rotative motion.
Watt's improvements to the steam engine, combined with Boulton's vision of a nation powered by steam, facilitated the rapid adoption of steam engines across the United Kingdom and, eventually, the United States. By the 1800s, steam engines were powering mills, factories, breweries and a host of other manufacturing operations. In 1852, the first flight of a steam-powered airship took place. Future iterations of the steam engine also came to define travel, as trains, boats and railways adopted the technology to propel passengers into the 20th century. [See also: How the Steam Engine Changed the World]
Follow Elizabeth Palermo on Twitter @techEpalermo, Facebook or Google+. Follow LiveScience @livescience. We're also on Facebook & Google+.
The Library and Lighthouse of Alexandria
In earlier chapters, we met the Alexandria of mathematicians and scientists, of astronomers and geographers, of anatomists and physiologists, and of poets and playwrights. Now we turn to another facet of the city’s endlessly multi-faceted personality, one which was there almost from the beginning but which arguably reached full flower only after the coming of the Romans: the Alexandria of engineers and inventors.
The tradition began with a man named Ctesibius, who comes to us only as a shadowy figure of legend from the glory days of the first three Ptolemies. One tale of his origins, so delightful that one has to hope it’s true, says that he was born a humble worker, the son of an Alexandrian barber. But, like a Henry Ford or a Steve Wozniak of another age, he was an inveterate tinkerer to whom invention came as naturally as breathing. His father’s shop benefited enormously from his talents when he was still a teenager he redesigned the mirrors the customers peered into, for example, so that they balanced perfectly at any angle. And then, broadening his horizons beyond barbering technology, he invented the first clock that we would recognize by that name today.
We must understand that Alexandrians’ conception of time at this point in their history was very different from our own. Their only form of clock was the natural one of the sun and moon and stars wheeling overhead, or at best sundials that reckoned time from light and shadow. (Fortunately, Alexandria was blessed with near-constant sunshine.) Your day began when the sun came up and ended shortly after it went down, and if someone told you to meet him at a given place at noon, you understood that to mean nothing more specific than “around the time that the sun is directly overhead” by necessity, schedules didn’t get any more precise than that. Luckily, there were no railroad timetables to keep.
The closest thing to a mechanical clock to exist before Ctesibius was a gadget known as a clepsydra — literally translated, a “water thief.” It was simply a receptacle with a spout at the top and a stoppered hole at the bottom. To use it, one filled it up with water, then removed the stopper. When the clepsydra was empty, an arbitrary amount of time — exactly how much was uncertain — was known to have passed. Rather than being used to count time in the abstract, the clepsydra was used to parcel out equal quantities of the precious resource. It might be used to ensure equal time during a political debate, or used in court to ensure that both the defense and the prosecution had the same amount of time to present their arguments. “Lawyers are driven by the clepsydra, never at leisure,” wrote Plato. Which is not to say that it didn’t have its applications for leisure-time activities: brothels allegedly used it to ensure that customers all got equal time with the girls or boys.
One might presume that it would be possible to measure more granular if still arbitrary units of time by waiting for the clepsydra to be half emptied, or a quarter so, etc. Certainly it would be simple enough to mark different water levels on the surface of a glass clepsydra. But it wasn’t quite that easy, due to a frustrating reality of physics: the more water in the clepsydra, the more quickly it flowed out of the hole at its bottom, thanks to the greater weight of water pushing on the whole from above. Thus the real halfway mark in terms of time would come at some indeterminate point well after the clepsydra was half empty of water. This meant that, while the clepsydra could be used to ensure equal time, it couldn’t be used to measure time in any real sense whatsoever — until Ctesibius.
His ingenious solution to the conundrum began with a second, much larger clepsydra mounted above the the first one, dispensing water into it at such a rate that the smaller clepsydra below it always remained full this ensured that water would flow out of the hole at its bottom at a constant rate. Another receptacle was then placed below this smaller clepsydra to capture this water. Markings on its surface allowed it to measure granular units of time with impressive accuracy.
From this start, Ctesibius’s water clocks evolved into gadgets of amazing sophistication, with feedback mechanisms that allowed them to run as long as the topmost clepsydra was kept full of water some were even capable of chiming the hour. It would be some 1800 years before a more accurate method of measuring time was devised.
A reconstruction of Ctesibius’s water clock in its mature incarnation. Water flows from the large clepsydra at the top to the much smaller one below it. A steady, predictable quantity of this water flows out of the spout near the bottom of this smaller clepsydra and into the larger oblong receptacle directly below it, whilst the excess falls into the overflow pan at the very bottom of the clock from another spout near the top of the smaller clepsydra which is obscured in this photograph by the figure of a man. A float within the oblong receptacle rises with the water level. The figure is linked via gears to the top of this float, and thus rises as well to point out the passing time on the measuring post, which is marked in twelve increments of five minutes each. When the float reaches the top of the receptacle after one hour has passed, it bumps into a mechanism which opens the spout at the bottom of the receptacle, emptying all of the water into the overflow pan, and returning the figure to the starting point of his journey, at which point the float bumps another mechanism to close the spout this is one of the world’s first known examples of an autonomous mechanical feedback mechanism. The clock will continue to run as long as someone keeps the large clepsydra reasonably full, which can be most efficiently accomplished simply by periodically emptying the overflow pan back into it. (Gts-tg)
The story goes that, having demonstrated his genius with his water clock, the humble barber’s son was invited to join the Museum of Alexandria — and, indeed, may have eventually become its head. He spent the rest of his life beavering away in his workshop, inventing more of the sorts of everyday conveniences for ordinary people which caused the rarefied likes of Archimedes to turn up their noses in disgust: pipe organs, lawn sprinklers, catapults.
Alexandria itself soon became known as the technological center of the ancient world, the place to come to buy gadgets both frivolous and practical. Alongside all of its other identities, it was a city of cogs and gears, of blowing air and running water — for, what with the absence of electricity, pneumatics and hydraulics had to serve in its stead. The docks and wharves of this eminently commercial city featured the most advanced cranes and hoists to be found anywhere in the classical world — “Give me a place to stand and a lever long enough, and I will move the world,” Archimedes had said — even as Alexandria boasted the most sophisticated indoor plumbing of any city of the era. Small wonder that, some 200 years after Ctesibius, the besieged Julius Caesar couldn’t help but admire the many intricate mechanisms his enemies rolled into place to oppose him. And yet the most astonishing days of Alexandrian engineering were still to come.
We know shockingly little today about the man with the auspicious name of Hero, who was widely regarded during his own time and long afterward as the most prolific inventor of complex, often semi-autonomous machinery that the world had ever known. We can identify even the rough era in which he lived thanks only to a lunar eclipse that we know to have taken place in AD 62, and which we find mentioned in one of his surviving writings thus we know that he was alive and active during that year. But there is, alas, little else we can say about Hero the man with any degree of certainty whatsoever. So, his writings about the things he made will have to speak for him. Many of them too have been lost to us, but a fair number have reached us, either in the original Greek or in later translations into Latin or Arabic. They speak eloquently of his extraordinary ingenuity.
The most lengthy and complete of Hero’s texts that has come down to us is known as the Pneumatica. In it, he describes no less than 75 separate devices. Some of them have, as he puts it, “useful everyday applications,” while others produce only “quite remarkable effects” these were designed simply for the pleasure of making them and watching them go rather than for any more practical purpose.
Even the allegedly practical inventions tend to have a more than a whiff of frivolity about them. Among the most amusing of them is the world’s first vending machine, which was used to dispense holy water to penitents in Alexandria’s temples. When one dropped a coin into a slot, it fell onto a pan that lay at one end of a tiny beam balance inside the machine. The weight of the coin forced the opposite end of the balance up, where it pushed open a valve, causing holy water to flow out of the machine and into the hands or cup of the eager worshiper. But the pan on which the coin lay was formed in such a way that the coin would eventually slide down and off of it, to fall into a repository of its brethren below. When this happened, the holy-water valve closed again until the next coin was deposited into the slot. The priests of the temple needed only fill up the machine with holy water from time to time, and of course collect the money that was constantly rolling in.
A reconstruction of Hero’s holy-water vending machine. (Gts-tg)
It would seem that Hero enjoyed a fruitful and presumably lucrative relationship with the priests of Alexandria. In addition to his holy-water vending machines, he provided them with the world’s first automatic doors, which they used to dramatic effect during their religious ceremonies. A hollow tube conducted heat from a fire burning atop one of their altars to a cauldron of water hidden in the basement of the temple. As its temperature grew hotter, the water expanded and was forced through a pipe to a heretofore empty bucket, which stood at one end of a beam balance whose other side was connected to a door via ropes and pulleys. When the combined weight of the bucket and the water it contained reached a tipping point, the beam balance moved and pulled the door open to admit the incorporeal form of a god, marking the climax of the ceremony above.
Hero’s automatic doors. (Public Domain)
Hero also invented a fortune-telling machine to automate the tedious work of priestly prophecy. It was a sort of Magic 8-Ball of the ancient world: pay a small fee, walk into a booth, ask the god a yes-or-no question, then turn a wheel to receive a (random) answer.
His inventions could be found in Alexandria’s theaters as well. He was a master of special effects, able to make curtains go up and down and props propel themselves about the stage, their movements “programmed” using a bewildering array of hourglass-style timers. When the actors complained about the difficulty of staying in sync with all of the other action happening onstage — once Hero started his mechanisms, there was no way to stop or pause them, meaning the actors had to adapt the performance to their inexorable progress — Hero resolved to cut real humans out of the show entirely. He thus began to develop his most astounding creations of all: intricate moving dioramas, in which life-size mechanical men played out scenes for the delight of crowds. We might go so far as to call him the world’s first roboteer.
Four centuries before Hero, Aristotle had dreamed presciently of a world where “every tool [is] able to complete its own task when ordered — or even anticipate the need.” He wrote of “shuttles that could pass through the loom by themselves, or plectra play the harp, master craftsmen [with] no need of assistants, and masters [with] no need of slaves.” Hero dedicated himself to bringing this vision to fruition in the context of entertainment at least, and appears to have had lots and lots of fun of his own in the process his joy of creation leaps from his descriptions of his inventions, a child’s delight in things that move and spin and whistle of their own accord. Small wonder that his contemporaries called him the machine man — a description that could apply equally well to some of the things he built.
In his book Automata, he describes one of his grand public dioramas, featuring the god of wine Dionysus, who was always a great favorite with the masses for obvious reasons. Let us picture the scene:
A roofed and elevated stage has been erected in the middle of a busy city square. Dionysus himself stands six feet (1.8 meters) tall at its center, holding a staff in his left hand and a cup of wine in his right, surrounded by dancing figures of Maenads, his libertine female followers. Altars stand some distance in front of him and behind him on the stage, a tamed panther lies at his feet, and the winged Nike, the goddess of victory, hovers above him. In response to a clockwork mechanism, run by ropes and pulleys and hourglass timers hidden beneath the stage, the god lumbers forward on a hidden track until he stands directly before the front altar, and Nike glides in the same direction to remain above him. He leans down over the altar, and fire flares up. Water, milk, or, if the crowd is lucky, wine shoots out of the end of his staff into the audience, fed via a hose from a reservoir hidden below him. At the same time, he casually turns the cup in his right hand, and a stream of wine flies in the direction of the thirsty panther. Meanwhile the circle of maenads begins to spin around him, accompanied by gear-driven kettledrums and cymbals. After a moment, the fire in the altar dies down, the music and dancing stop, and Dionysus and Nike rotate a neat 180 degrees, to return to the center of the stage and thence onward to the altar at the other side, in order to delight the crowd standing over there with the same pantomime. When the robot performers return to the center of the stage once again, a harried human attendant hidden in the bowels of the mechanism hastily resets everything, then sets it in motion again.
Hero also made smaller dioramas, on the scale of a puppet show, which made up for their lack of size in their even more intricate, even more finely honed complexity. One of them, also described by its maker in Automata, told a complete story that took place over five separate scenes. Its protagonist was Nauplius, the king of the Greek island of Euboea during the Trojan War. Nauplius’s son went to join the fray in Troy like most young Greeks of noble birth, only to meet a tragic end there. In the version of the tale whose sequel was presented here, the son crossed the hero Ajax in one of the Greeks’ many internal disputes over strategy and lost his life for his trouble.
As the first scene of Hero’s mechanical play begins, the Greeks have sacked Troy at long last and are preparing to return home in triumph. Nauplius, however, has asked the goddess Athena to avenge the murder of his son. Here is how Hero himself describes the action that follows:
At the outset, when the box opened, twelve painted figurines appeared: these were divided into three rows they were made to represent some of the Greeks refitting their ships and busy launching them.
These figurines moved, some sawing, some working with axes, some with hammers, some others using bow-drills and augers, and they made a lot of noise, just like in real life. After sufficient time elapsed, the door closed and opened again, and there was another arrangement the ships, in fact, were shown being launched by the Greeks. After [the box] closed and opened again, nothing appeared in the box except painted sky and sea.
Not long after, the ships sailed in line ahead, and some were out of sight, some in view. Often dolphins swam alongside too, sometimes plunging into the sea, sometimes visible, just like in real life. The sea gradually grew stormy, and the ships ran uninterruptedly. After [the box] closed again and opened, none of the sailing ships was seen, but Nauplius holding up the torch and Athena standing beside him were seen.
Fire blazed up above the box, as if a flame appeared on high from the torch. After [the box] closed and opened again, the wreck of the ships appeared, and Ajax swimming and a machine was raised above the box, and as thunder rumbled in the box itself a bolt of lightning fell on Ajax, and his figure vanished. Thus, when the box closed, the story came to an end.
The invention of Hero that is the most hotly debated of all today was apparently created as just another form of entertaining spectacle. Yet it carried within it the seed of something infinitely more useful. Hero created nothing less than the first documented example of an engine powered by steam — also the first example of a reaction turbine of the sort used in a modern jet airplane.
The device that has become known as Hero’s engine starts with a closed cauldron of water mounted just above a fire pit. The lid on top of the cauldron has two pipes running up to a hollow sphere which is mounted such that it can rotate in place along a single axis. A pair of narrower, L-shaped tubes to nowhere are affixed to the surface of the sphere, their outlets reciprocal to its axis of rotation.
When one kindles a fire below the cauldron, it heats the water inside, producing steam which runs up through the pipes into the sphere, then out through the narrower tubes. This causes the sphere to spin of its own accord. The hotter the fire becomes, the more quickly the sphere will spin, in the midst of a whistling haze of steam. It must have been a very impressive sight for people unaccustomed to seeing non-living objects of any sort moving of their own accord.
Hero’s steam machine. (Public Domain)
But we have no evidence that Hero or any of the Alexandrians who followed him ever even thought about turning this parlor trick into a practical machine. Was this down to a colossal lack of vision, as some have wished to believe? Could Hero’s engine have been made to do real, useful work for the people of Alexandria? John G. Landels, a historian of ancient engineering, is decidedly skeptical of the notion.
Could this form of steam engine ever have been used as a practical power source? The answer is, almost certainly not. It operates best at a high speed, and would have to be geared down in a high ratio. Hero could have managed that, since the worm gear was familiar to him, but not without friction loss. Inadequate heat transfer from the burning fuel to the cauldron would keep the efficiency low. It is in the realm of possibility that, given the technology of Hero’s age, overall efficiency might have been as low as one percent. If so, then even if a large-scale model could have been built, to deliver .1 horsepower and do the work of one man, its fuel consumption would have been enormous, about 25,000 B.T.U. per hour. The labour required to procure and transport the fuel, stoke the fire and maintain the apparatus would have been much more expensive than that of the one man it might replace, and the machine would be much less versatile.
Still, one can easily enough imagine Hero’s engine as a stepping stone to a far more useful form of steam engine. Those which powered the Industrial Revolution of the late eighteenth and early nineteenth centuries used steam to drive pistons inside sealed cylinders rather than venting it to the open air for the amusement of spectators. Most of the parts necessary to build just such a contraption were very familiar to Hero. A type of hand-driven pump called a force pump, long in use in Alexandria and elsewhere — in fact, Ctesibius was sometimes claimed to be its inventor — utilized pistons and cylinders and rocker arms uncannily similar to those of an Industrial Revolution-era steam engine. And whilst experimenting with the use of hydraulics to drive fountains, Hero himself designed and made valves adequate enough for this type of steam engine. Could the Industrial Revolution have arrived 1700 years early if this one man had but had a different set of priorities? It’s a tempting thought to contemplate.
In fact, some have been tempted by that thought into making disparaging judgments of Hero the man, portraying him as a natural genius who wasted his gifts on trivialities delivered for personal financial gain. In his authoritative two-volume study Greek Science, Benjamin Farrington writes with something close to sarcasm of how Alexandrian science,
when it lost its ambition to transform the material life of man by being applied to industry, quickly acquired fresh application. It became the handmaid of religion and was applied to the production of miracles in the Serapeum and other temples. To the conscience of the age, these scientific aids to devotion hardly differed in principle from the use of improved lighting effects or the introduction of organ music, which were also achievements of this age. They were intended to create a pious public, to make religion attractive and impressive, and seem to have done so. When science began to flourish again in the modern world, it had another purpose than to deceive.
But was the purpose of Hero’s many inventions really to “deceive?” And did the people who witnessed his “miracles” really believe that they were the products of gods? We can plainly see in many of the texts of the early first century AD that religiosity was in marked decline among the intellectual classes of that period. Many, many authors treated the gods more as metaphors than as living entities, or chose to ignore them altogether. It’s of course possible and even likely that sincere religious belief was more prevalent on the streets of Alexandria than inside the city’s museum and library, but did even these people really believe that the gods were the engines behind Hero’s clockwork miracles? I suspect from the tone of his surviving texts that he saw himself as a showman giving the people a good time with an accompanying wink and nudge, like an ancient P.T. Barnum, and that the people he supposedly duped probably saw his productions in the same light, and willingly suspended their disbelief in the same way that we do when we go to see a stage magician today. The religiosity that would eventually overwhelm the daily life of the Alexandrian streets would be, as we’ll see in later chapters, of a very different character from Hero’s showy pagan spectacles.
The issue of whether Hero should have been doing something “better” — something more serious — with his undeniable genius is a thornier one. On the one hand, it’s true that there are no equivalents of Archimedes’s screw pump or Ctesibius’s water clock in his catalog of inventions, only relatively frivolous tools for commerce or entertainment. But on the other hand, we should not be too quick to judge him, given that we know literally nothing of the man’s circumstances, nothing about what combination of compulsions and opportunities might have led him down the the path he followed. And then, simply providing joy and entertainment to others is a worthy end in itself, one which our modern culture values enormously.
These known unknowns haven’t kept Hero’s apologists from defending the man just as spiritedly as his detractors have condemned him. All sorts of wild possibilities have been mooted by way of justifying his failure to build upon his proto-steam — and proto-jet — engine in particular. Perhaps he actually did keep working on it, only to have it blow up in his face and kill him. Or perhaps it exploded and merely frightened and/or injured him badly enough that he left off further experimentation. Since we know nothing concrete of him beyond our record of his inventions, we must acknowledge both as possibilities at least — although one does have to suspect that an exploded Hero would be a remarkable enough story that some ancient scribe whose writings have reached us would have mentioned it.
In the end, though, debates like these are moot because the fate of steam power in Alexandria never really depended on one man at all. It’s romantic and soothing to our humanistic egos to believe in the decisions of individuals as the hinge of historical fate, and occasionally it’s even a defensible way to think about history — but almost never the history of science and technology. Had steam engines been obviously useful in first-century Alexandria, someone else if not the man himself would have built upon Hero’s work. The real stumbling block to a steampunk Alexandria wasn’t a lack of knowledge of pistons and cylinders, rocker arms and valves, nor even the considerable limitations of ancient metallurgy. It rather came down to the vagaries of economics and culture.
The Industrial Revolution of our actual history ran on coal, a substance which was almost unheard of in ancient Alexandria. The vastly less efficient fuel of wood was commonplace, but still much more expensive than in other cities, what with Egypt being such a timber-poor land. Meanwhile the wealthy elite of Alexandria had millions of laborers already at their disposal. They had no motivation to invest in steam technology as long as human capital was so cheap. Purchasing enough fuel to feed virtually any conceivable ancient steam engine would have cost far more than any value such an engine could add for its owners over simply ordering others to do its work by hand. The cost in drudgery to the laborers was of course another matter entirely, but that’s a hopelessly anachronistic way of thinking about the question.
Lest we be tempted to judge these ancient Alexandrian elites too harshly, we should remember that they had never seen an industrial revolution, and had no idea what such a thing might look like or, indeed, that it might come to exist at all. Likewise, the caste systems that arbitrarily made people of leisure and intellect of a few, poor laborers of most, and slaves of a substantial minority was as deeply intertwined with their society’s conception of itself as the egalitarian ethos is with so many of our own. We can, however, take some solace in noting that some of the groundwork of our modern conception of society, which I as a product of my own times naturally find to be a fairer, juster way to live, would be laid in the Alexandria of the centuries immediately after Hero. Unfortunately, much of the empirical practicality that made his gadgets go would be retired during the same period — retired not only in Alexandria but in most other places as well, and for many, many centuries to come. So, the Industrial Revolution would just have to wait until all of the pieces were finally in place at the same time.
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One of Heron's lasting contributions to science is the syringe, a device he used to control the delivery of air or fluid with precision. The device, as with modern syringes, used suction to keep air or liquid in place and, when the plunger was depressed, this forced the liquid out at a controllable rate. This device, while much larger than the tiny modern syringes, is unmistakably their ancestor.
Heron's fountain was an enigmatic invention, a fountain that seemed to power itself, and used some very sophisticated pneumatic and hydraulic principles. The fountain contained two reservoirs, one of which was filled with water. As water was poured into the upper tray, it flowed down to the first reservoir, where it compressed the air.
This compressed air was forced into the second reservoir, where it forced the water out and created a powerful jet. This device operated until the bottom reservoir became filled with water, when it had to be reset.
Heron of Alexandria and his Aeolipile
The man credited with invention of the aeolipile, identified as either ‘Hero’ or ‘Heron,’ was a Greek who lived in Alexandria, Egypt, from about 10 to 70 A.D. A diagram of the aeolipile built by Hero is shown at the left. In this device, steam was generated by a fire under a closed pot of water. The steam entered the ball through the vertical tubes connecting the ball to the heated pot. The steam escaped from the ball through the tubes that are bent at a 90o angle, so that the jet action from the exhausting steam caused the ball to rotate.
The rotational motion could have been put to productive use driving machinery, but there is no evidence that it was put to that use. It seems that it was mostly a toy or a demonstration that was used in temples.
What did the hero of alexandria invent
What could have developed in Alexandria had the city not been sacked and burned by the Romans? Entertainment seemed to captivate Hero, and some of his most intriguing inventions were designed for audiences. The invention was a steam-powered cannon, fueled by water heated over coals.
(This realization possesses great applications, despite it being contradicted, in certain extreme cases, by Einstein.). Credit Rome, The Fall of Greece and the Rise of Rome: The Role of Pyrrhus and His “Pyrrhic Victories”, Seeing through Art: Waldemar Janusczcak’s Iconoclastic Vision, Making Something Out of Nothing: The History of Zero (from Babylon to Outer Space), Pyramids, Sphinxes, and Aliens?
design worked on the principle that liquids in a closed system seek a common level. For example, Hero of Alexandria (mid-1st century.
Only fragments of other treatises by Heron remain.
Based on Hero’s rescued writings, we know that the scientist and educator had mastery of quite a broad range of subjects. These vending machines allowed each member to receive an equal allotment of holy water without requiring the presence of the priest. A = Square root of√s(s−a)(s−b)(s−c)
By some accounts, Hero invented over 80 novel machines, only a few of which were evidently constructed in his lifetime. Two millennia ago, in the great cosmopolitan center of Alexandria, there lived a man named Hero, a scientific experimenter and inventor who developed breakthrough applications for steam hydraulics, wind power, and even programmable automatons. c. 270 bc).
Hero must have been deeply involved in the religious practices ofEgypt under Alexandrian rule.
These included, among others, Metrica, the study of measuring volumes and areas of 2-D and 3-D geometric shapes Mechanica, the study of lifting and moving heavy objects Pneumatica, the study of pneumatics, hydraulics, and other uses for air, steam, and water pressure and Automata, the study of machines built to elicit reactions of wonder, particularly in temples of worship. A prime example of these religion-oriented devices was the “. Harnessing the power of water heated to boil in a virtually closed chamber with two small vents, Hero was able to demonstrate that steam is created in an energetic transfer between two states of water, liquid and gas. However, the invention of the first steam-propelled mechanism, the aeolipile, dates to the first century BC and can be credited to Hero of Alexandria, an Alexandrian scientist and inventor. Our editors will review what you’ve submitted and determine whether to revise the article. It’s tragic to consider that most of his work was lost for nearly two millennia.
Such ponderings, in their humble way, are in service to the inquisitive intellects of Hero and other great scientific thinkers. This is because many of his mechanical inventions attempted to create illusions of divine intervention and activity in the temples of the day. From the Sphinx to the Pyramid of Giza, from ink to agricultural tools, here’s a look at how (and why) they did it.
The ancient Greeks had already been playing around with the uses of steam from the fourth century BC.
A prime example of these religion-oriented devices was the “automatic door opener” that was designed for use as part of a spiritual service. These included, among others. If nothing else, Hero made a lasting contribution to science and medicine with the invention of the syringe. Hero's holy water vending machines could be found in temples across the land.
As the rope was pulled through the device, the knots moved levers which caused actions to happen on the miniature stage.”. Hero’s. Get exclusive access to content from our 1768 First Edition with your subscription.
Included is a derivation of Heron’s formula (actually, Archimedes’ formula) for the area A of a triangle, Using a hidden heat source that cr… An example that really stands out is the ever-needed invention of the self-refilling wine glass. Based on Hero’s rescued writings, we know that the scientist and educator had mastery of quite a broad range of subjects. By signing up for this email, you are agreeing to news, offers, and information from Encyclopaedia Britannica. It ends with the description of an odometer for measuring the distance a wagon or cart travels. Hero’s fire engine was an early marvel of hydraulics. In 1938, Hero’s description of this eclipse allowed science historian Otto Eduard Neugebauer to match it with the event which took place in Alexandria at 11 pm on March 13, 62BC- thus establishing Hero’s period as the first century BC. Heron of Alexandria was one of the finest mathematicians and inventors that the world has ever known. Omissions? According to Leonardo da Vinci, the fourth-century Greek scientist Archimedes invented one of the first steam driven devices in 330BC. His numerous inventions (at least 80 are recorded in his notes) included the first hydraulic-powered fire engine as well as the first deliberate use of wind power in a man-made machine.
Heron of Alexandria, also called Hero, (flourished c. ad 62, Alexandria, Egypt), Greek geometer and inventor whose writings preserved for posterity a knowledge of the mathematics and engineering of Babylonia, ancient Egypt, and the Greco-Roman world.
Waldemar Januszczak is seeking to change that by hosting TV documentaries on art that feature his accessible yet iconoclastic style, making art lively, never stodgy, for his audience. He published a detailed description of a steam-powered instrument called an ‘aeolipile,’ which is also known as ‘Hero’s engine.’ This work is cited by Pappus of Alexandria (fl. Although classical scientists never fully explored the potential of Hero’s aeolipile in ancient times, its technology may have informed steam-based technology even before Papin’s time. Not much. Viewing art can be a solitary, sometimes confounding experience.
” that was designed for use as part of a spiritual service. Mechanica, which is closely based on the work of Archimedes, presents a wide range of engineering principles, including a theory of motion, a theory of the balance, methods of lifting and transporting heavy objects with mechanical devices, and how to calculate the centre of gravity for various simple shapes. He also invented a coin-operated holy water dispenser and a self-powered portable fountain that appeared to operate on its own, not even needing an external water source. According to one writer for, , “the device was controlled by a series of ropes with knots tied in them.
The Afterlife Of Ancient Alexandria
Roman Amphitheater archaeological remains in Alexandria, 4th century AD, via Ancient History Encyclopedia
In 641, Alexandria fell to Arab invaders. Its core population was so devoted to their own version of Christianity, the Coptic Christians remained under Muslim rule, and are still an important group in Egypt today. The center of global learning shifted dramatically with the rise of the Islamic empires, and the city of light is this period, was the beautiful city of Damascus, and later the city of Baghdad.
The great city of ancient Alexandria would eventually be swallowed by the ocean. The great library was burnt at an unknown date that is still heavily debated by scholars. The lighthouse and Alexandria’s other wonders were destroyed by war and decay or buried under sand. Yet Alexandria’s influence would live on the texts produced there would drive the Renaissance and the Islamic golden age.