The only measurement tool in the book and why al-Jazari is the first engineer

Introduction

Al-Jazari tells that when he mentioned to some people that any(not colinear) three points could be position on the circle they didn’t believe him, so he built the only measurement instrument in the book to find the center-point of three points of unknown position. The device is quite straight forward, but we can learn quite a bit from his choice to solve, what is clearly a mathematical problem, with an “engineering” solution.

An Instrument for finding the center of a circle, Topkapi, 1206

How does it work?

The technical explanation is so short that I decided to make an exception and not color it in blue. I hope you can forgive me. Al-Jazari took a ruler and built a vertical on the center point. He placed his instrument between the two points; found the center point and drew a perpendicular segment. He repeated the process for two more points. The intersection of the perpendicular segments is the center of the circle and the distance to each point is the radius. Besides, similarly to angle measuring instruments, there is an ark, which allows to measure and mark different angles.

Some Math

One can prove that any three points that are not colinear (al-Jazari was aware of this point and specify it explicitly) are on a circle in two approaches:

  • Euclidean geometry
  • Analytic geometry.

In Euclidean geometry, three points which are not colinear form the vertices of a triangle. All triangles can be within a circle. The center of the circle is the intersection of the three perpendicular bisectors. It is relatively easy to prove. If you want to practice your Euclidean geometry, look at the diagram below, build the three radiuses BO AO CO and prove they are identical using triangle congruence theorems. Euclid’s “Elements” was translated into Arabic relatively early in the House of Wisdom in Baghdad (بيت الحكمة )). There is no direct reference in al-Jazari’s book to Euclid, but his device is based on this theorems:

Right side drawing from my Euclidean geometry book, on the left a drawing by al-Jazari.

In a different approach, you can find the center circle with analytic geometry:

Circle equation, Analytic geometry

When:

r is the circle radius

a,b are the coordinates of the center point

Since the triangle has three vertices, we have three equations in three unknowns (a, b, r) and an immediate solution. Analytic geometry has roots in ancient Greece and Persia of the 11th century, but the breakthrough was made by René Descartes, philosopher, scientist and mathematician. We remember Descartes mostly because of the proposition “I think, therefore I am.” Descartes was a remarkable mathematician and the first to offer a system of axes (x, y), as in the diagram above, which is named after him: Cartesian coordinate system. It allows the graphical representation of functions. Generations of mathematics students were, are and will be very grateful. Also, he took advantage of the Cartesian system to connect geometry and algebra, creating analytical geometry. Descartes was an impressive polymath, his contributions to philosophy and mathematics are the pillars of the two disciplines, but he also was a key figure in the Scientific Revolution and made a contribution to optics.

Polymath and al-Jazari, the first engineer

A polymath (Greek: πολυμαθής) literally “having learned much” is an individual whose knowledge spans a significant number of subjects. Both in English and Hebrew we often use the term “Renaissance man” although all the “engineers” before al-Jazari were actually polymath long before the Renaissance:

Archimedes was a gifted mathematician, scientist, and engineer, who invented the “Archimedes Screw” (a pump, still used to this day), he has improved the power and the accuracy of the Catapult, made a giant crane known as “Archimedes Claw” not to mention the myth (?) of burning the Roman fleet using mirrors. All this pales in comparison to his contributions to mathematics and physics. Archimedes anticipated modern calculus and analysis by applying concepts of infinitesimals, developed the concept of buoyant force in “On Floating Bodies” and gave the mathematical explanation to the lever.

Hero of Alexandria was an engineer, mathematician, and physicist.  Hero may have been either a Greek or a Hellenized Egyptian. It is almost certain that Hero taught at the famous Library of Alexandria because most of his writings appear as lecture notes. He is known for his research in hydrostatics, but I have already written about Hero concerning his book on automata, he also built the Aeolipile, the first steam engine. In mathematics, Hero described a method for iteratively computing the square root of a number, but his name is most closely associated with Hero’s formula for finding the area of a triangle from its side lengths.

The Banū Mūsā (“Sons of Moses”) were three 9th-century Persian scholars who lived and worked in Baghdad. The Banu Musa wrote almost 20 books, the majority of which are now lost. They are known for their Book of Ingenious Devices on automata and mechanical devices. I wrote about them in the context of the fountains, but in the context of a polymath, we can mention their contribution to mathematics, The most important work of theirs is the Book on the Measurement of Plane and Spherical Figures, a foundational work on geometry that was frequently quoted by both Islamic and European mathematicians.

Al-Jazari is not like that. His contribution to engineering is diverse. I mention already the automata and the use of the camshaft, the significant advances in candle clocks [Hebrew] including the invention of the bayonet connection, the thermal insulation, the double-action pump but he was not involved in science or math or other fields outside engineering.

The concept of the Renaissance man was coined by Leon Battista Alberti ” A man can do all things if he but wills them”, a manifestation of the deep humanism in the roots of the Renaissance. The basic premise is that the infinite human ability to evolve, and we must embrace all knowledge in our way to develop our abilities. The world has expanded so that it is just impossible. Thomas Young, an English polymath in early 19th century, regarded by many as the last man who “knew everything” was skilled in medicine, physics, Linguistics, harmony (music) and even accounting. The web site of the Israeli medical association includes thirty-two different major specialties and more, numerous subspecialties. It is not possible, even theoretically, to complete all medical specialties during one life, let alone in other areas.

We live in a more skeptical and concerned world. We ask our children, already at a young age, “What do you want to be when you grow up? We narrow the field in high school and ask the students to find majors area of study where they excel. We have institutions, counseling centers, and tests to help young people choose their profession. A physics student will get the necessary mathematical background but will not receive academic credit for courses in Assyrian or typography. In second degree studies, we reduce the field of study further, and in Ph.D., we focus on one question only. As a society, we look at people that change profession with concern, maybe as less stable who lack the ability to focus.

Following Donald Hill, The book translator, and annotator and somewhat because of my own training, I thought that using an instrument (instead of a formal proof) indicates a limited background in mathematics. This may be true. My Love M. commented that mathematical proofs are less approachable to most people and lack the magic of the instrument al-Jazari built. Al-Jazari was the first “pure engineer” not because of lack of mathematical background, or ability in math and science, but because of his passion for engineering and his ability to translate abstract and formal issues to instruments.

The Musical Boat for a Drinking Party

Introduction

The Musical Boat is the fourth of ten automata (mechanical dolls) and vessels that were designed to amuse guests at drinking parties at the King Court in Diyarbakir. On the boat deck seat the king, his and weapon-bearer, a slave holding a jug and goblet, as if serving drinks. Below there is a group of boon-companions and four slave girls, a flute-player, a harpist and two tambourine-players. The King and his court are static, papier-mâché sculptures. The musicians are made from jointed copper, and their arm can move. Professor Noel Sharkey sees in the unique mechanism al-Jazari designed for the drummer the world’s first programmable robot. More on this topic, below.

The musical boat, Topkapi manuscript, 1206

How does the boat work?

The boat moves gently on the surface of the pool at the Palace. Once every half hour, without any external intervention, a performance begins; The flutist would play the flute, the drummer would beat the tambourine, and the harpist plucks the copper strings. Here is a short mute (unfortunately) video of a model of the musical boat. After approx. Fifty seconds you can see the mechanism in action.

 

The technical explanation, as always, will be colored in blue, so anyone who is not interested in tipping buckets or early camshafts can skip those bits. The diagram below is the original drawing of al-Jazari with my captions:

The slave girls (musicians) are sitting above a water reservoir. The tank empties slowly into the tipping bucket. When the tipping-bucket has filled, after about half an hour, it discharges its water onto the scoops wheel, turning the wheel on its axle. The pegs on the axle rotate as well moving the rods which are connected to the slave-girls’ hands, moving them up and down. This creates the motion of the harpist plucking or the drum beating. The harpist has a three peg system for one hand, and the other hand is operated by one peg only. The rods are an early version of a camshaft and convert the circular motion of the axle to the linear movement of the musicians’ hands. The spacing between them generates different patterns of drumming or harp music. The water flows down into the pipe which is connected to the air vessel, forcing air through the whistle. This is the source of the “flute” sound.

Qiyan – Musician slave girls

The drawings in the facsimile edition were not done by al-Jazari. Donald Hill, The book translator, and annotator, detailed eleven manuscripts all over the world. The earliest copy, now in Topkapi Library (MS 3472) was completed by Muhammad Ibn Yusuf Ibn Uthman alHisenkafi in April 1206 and is the source of a facsimile. When a scribe finished copying a manuscript, a task that lasted weeks or even months, he would add a colophon, brief statement containing information about the publication such as information about the scribe and the manuscript. This is how we know that this copy was completed in 1206, the year al-Jazari died. We can assume that this copy was prepared from the original book, and the drawings are quite similar to the original. This is interesting because of the affinity between the Clothing of the boon- companions and the slave girls. The boon companions and the girls are all wearing qaba, a robe with sleeves, at mid-calf –between the knee and ankle that has a diagonal fastening of one side over the other. The color scheme is also identical. This made me think of them as “male musicians” Although the text is very clear about slave girls

Qiyān (Arabic: قِيان‎, ) was a social class of slave women, trained as entertainers, which existed in the pre-modern Islamic world. Qiyān is often rendered in English as ‘singing slave girls,’ but this translation does not reflect the fact that qiyān were skilled entertainers whose training extended well beyond singing, including composing music and verse, reciting historical or literary anecdotes, calligraphy, or shadow-puppetry and more. Qiyān were important in performing and distributing the works of the composers of the period in the Palaces of Islam from the eighth to the thirteenth century. They received broad education from an early age, including science, philosophy, and art. Beyond being gifted poets, dancers, or musicians, they were supposed to be courtesan with high conversational skills. There’s quite a bit of information about Qiyan in Baghdad, the Abbasid capital. In these years Bagdad was a cosmopolitan city and the center of science, culture, and philosophy. The musical slaves came from different cultural backgrounds. We know of Qiyān from all over the world, from Rome to India. They were bought in for outrageous sums of money, but the slavery is somewhat confusing, and those released remained in palaces in the same role? You can’t compare the tiny principality of the Artuqid with the Abbasid caliphate in Baghdad, but the presence of the Qiyan in Diyarbakir is another indication of the cultural flourishing in line with the original architecture  [Hebrew] and the initiative to write the ” Book of Knowledge of Ingenious Mechanical Devices.”

Musical robot

The word ‘robot’ was first used by Czech writer Karel Čapek in his 1921 play R.U.R -Rossum’s Universal Robots. The word ‘robot’ itself was not new, and come from Slavic language robota, meaning servitude. Oxford dictionary definition, “a machine capable of complex operations automatically, especially with programmable computer” is problematic, if only because my car is capable of a complex series of actions automatically, it has a large number of programmable electronics, and it is not a robot by any definition. In literature and science fiction movies, we use “robot” for an android, a machine resembling a human being and able to replicate certain human movements and functions.

Čapek’s book was written in 1921, long before Ted Hoff invented the microprocessor. When we talk about ancient robots and the automata al-Jazari built and ask ourselves if they should be considered as the predecessors of robotics, the questions should be two:

  1. Was it possible to program? Or in other words, do they have the ability to do different actions by design?
  2. Do they have autonomy? The ability to decide what to do and how to do it?

The question of “what was the first device that could be programmed?” is more theoretical than practical, but the musical boat is a leading candidate. Professor Noel Sharkey of Sheffield University built a model of a single drummer from the musical boat to illustrate how it can be “programmed.”  Beneath the ‘drummer’ was a rotating shaft with pegs on it. As these pegs rotated they pull on a lever that raised the drummer’s arm and then it dropped to hit the drum. The placement of the pegs entirely controlled the rhythm and timing of the drum beats. The purpose of the model was to demonstrate that one can play different beats using different peg patterns by changing the peg locations and spacing.

Did al-Jazari actually “program” the musical boat? We will never know. He probably used this method during the design to get the rhythm he liked. Whether it was used or not, the musical boat shows the possibility of “programming.” The question of autonomy will have to wait eight centuries until engineers would have sensors and computerized systems.  For those who want to expand, I attach a short (about ten minutes) film from the history channel. It introduces the subject of Robotics and the contribution of al-Jazari and other ancient robots. For some reason, they turned al-Jazari into a Persian?

The Drummers’ Clock and Musical Robots

Introduction

The Drummers Clock is a water clock and probably one of the first drum machines and musical robot ancestor. It features five mechanical drummers: two cymbal players, two drummers with a drum slung over their shoulder and a drummer sitting in front of two kettle drums. Despite significant advances in robotics and AI- Artificial Intelligence musical robots fall short in comparison to human musicians, their music lacks subtleties and is “mechanical.” The simplicity of the drum machine in contrast to a robot violinist helps to focus on the real issue. This post is moving between explanations of the drummers’ clock and thoughts on the difficulties in creating a “musical” musical robot.

The Drummers’ Clock, a dispersed copy, 1315

How does it work?

This is a simple version of the Castle clock with fewer mechanisms to display the time, and those that remained are simpler. The large components: Water tank, float, and the flow controller are identical to the Castle clock and the “Time cart” is very similar, a little like a cheap version of a mobile phone. Al-Jazari does not explain them again but refers the reader to the first chapter (the Castle clock). I also turn directly to musicians. Al-Jazari writes:

 “When an hour has passed the musicians (نوبة – nūbah, a musical genre found in the North African, it has its origins in Arabo-Andalusian music.) perform with a clamorous sound which is heard from afar.”

The technical explanation, as always, will be colored in blue, so anyone who is not interested in tipping buckets or scoops wheels can skip those bits. The diagram below is the original drawing of al-Jazari with my captions.

The water flows on the scoop wheel once an hour. This is a large clock and every time about eight liters of water flows. It is turning the scoop wheel on its axle so that the pegs move the rod which is connected by a copper chain to the slave-girls’ hands. The pegs are an early version of a camshaft and convert circular motion to linear movement. The number of pegs and the intervals between them create different patterns of drumming. The copper strip goes through the hollow wooden body of the musician and when it is pulled it goes up and later falls to hit the drum. The pegs are organized in a way which is characteristic of the work of al-Jazari, two adjacent pegs, and a third peg apart. The result is two relatively fast beat, and a third after a pause. There are also two trumpet players but they only “decor accessories.” The sound of trumpets is produced separately by the water pouring into an air vessel and compressing the air out through the pipe with a whistle.  Al-Jazari used this in many devices, including the Perpetual Flute.

Robotics and the student’s disappointment

Robotics is an enjoyable and sometimes exciting way to teach and learn science and technology. This is true for excellent students and students with difficulties in mathematics and science. Most of the student gladly take upon themselves robotics problems, research a topic, and build a robot using original thinking and their ideas. I taught robotics in different settings: in elementary school Gavrieli, in middle school Branco Weiss and at the Davidson Institute of science education. In all the years I taught, I found it a creative learning experience. Beyond the programming tools, mechanical engineering, electronics, and sensors, it teaches children to confront and overcome obstacles, builds confidence and self-esteem, and gives inspiration to science and technology. As a part of the introduction, I would present a wide range of robots, including a robot that plays the violin:

In almost every class I taught, students (happy and enthusiastic) were complaining that the robot’s performance is, “mechanical” or “robotic” as a weakness. Violin has a wealth of nuances in the way the violinist produces the violin sound (Timbre). This is the result of many choices such as which string to use, the pressure of the bow, the point of contact, the bowing speed, to use the whole bow, or only partially. All these choices reflect the musical understanding of the violinist and will echo emotionally with the listener. The Musical robot in the movie is programmed so that it “knows” to play the notes, but it has no musical understanding at all the concept of an artistic interpretation is foreign to him. The drum machine is much simpler in comparison to the violin and will facilitate the discussion.

The drummer’s choice includes “merely” the question of the drums selection and the beating template. In terms of the drum machine of al-Jazari, this is the arrangement of the pegs for each drum and possibly changing the length to affect the volume. Al-Jazari made these decisions during “programming” or the design phase, but we can easily think on modern drumming robot with all parameters free to change in real-time. This will allow changing hand techniques, and evolving drum beat patterns but will not progress us even one step toward musical interpretation.

This is a nontrivial challenge for robot builders. Robots in science fiction literature and toward the end of the 20th century are machines that can replicate human action, especially when it is repetitive. When Karel Čapek coined the word “robot” in the play R.U.R (Rossum’s Universal Robots), the idea was to replace humans when the work is tedious and difficult, or even dangerous. Obvious examples are the welding robots in the automotive industry or the Police Bomb Disposal Robot. In recent years, there is a shift in direction, and a lot of research is done on Artificial Intelligence (AI). There are exceptional results in various fields, including robotics stock traders, diagnostic medical robots, and precise surgery robot. What was considered thirty years ago unsurmountable like software playing chess or go (Japanese board game) is a reality. Chess software like Komodo can beat any human grandmaster. The contribution of AI to music (AIM- Artificial Intelligence Music) is more modest and limited, at this time, to conferences and academia and no robot can be matched to a human musician and people are not jamming concerts to listen to musical robots. AIM is a broad field and includes many topics, some of which are relatively simple to understand, Like:

  • Methods to produce music using musical robots
  • Storage and of digital music

Some are more complex, but still approachable:

  • Symbolic representations of music – how to represent music, beyond the note including “human touch” and interaction between musicians.
  • Human-computer interaction-music – how can a computer respond to music, including jazz improvisation.

Some are borderline science fiction:

  • Cognition Computational music-the idea is to try to teach the computer what is needed for music playing or composition. Moreover, to treat this as a process and do the same learning that does a composer/performer.

As someone who likes robots and automatons, maybe like al-Jazari at his time, I’m surprised from the pleasure I get from reading about the difficulties of the AIM community and the human abilities which are so hard to imitate. Despite what I wrote I would like you to see the film below: I don’t know how it was done and what part is human, and what part is AIM but it is certainly fun to watch and listen!

The basin of the Peacock and the magic of automata

Introduction

The basin of the peacock is an automatic basin for the ritual ablution- Wuḍū (وضوء). A servant brings the basin and positions it so that the beak of the peacock is facing the master. The servant pulls a hidden lever in the tail of the peacock, and water begins to flow. Then the left door opens, and mechanical slave emerges holding soap. Toward the end of the washing, the right door opens, and another mechanical slave emerges, this time, holding a towel, to dry the master’s hands. The automata are important to the history of technology. Methods invented to refine automata laid the basis for modern technology, but I hope in this post to talk about the source of the magic of automata.

Basin of the peacock, Topkapi manuscript, 1206

How Does it work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in siphons or automaton mechanism can skip those bits.

The hollow Peacock is made of copper, large enough to contain the water needed for the purification ceremony. The arched neck is a siphon. A siphon is a tube in an inverted ‘U’ shape, which causes a liquid to flow upward, above the surface of a reservoir, with no pump, but powered by the pull of gravity. The siphon will work while the water in the peacock’s body would rise above the bend in the peacock neck. The peacock’s tail, which is spread out, is divided into two volumes. The bottom part is connected to the body of the peacock. The top is separated with a conical plug. This plug is connected by a curved lever which reaches the cover of the tail. At first, the servant fills the water when the plug is open, thus filling the body of the peacock and the lower half of the tail then he pushes the plug. At this stage, the water level is below the bend in the peacock’s, so nothing happens. With the plug in place, he fills the top half of the peacock’s tail and brings the basin to the king. Now the servant pulls the plug and connects all the Peacock parts. The water came down and rise over the bend of the Peacock neck, and the ritual ablution begins.

Al-Jazari and  Donald Hill settled for a side drawing, but my love M. insisted that it’s hard to understand the operation of the automaton without a frontal drawing. So I expanded the drawing:

When pouring water into the basin, the water flows through a hole in the floor into the lower chamber, and the float goes up until it pushes the mechanical slave holding the soap, causing him to move forward and open the left door and thus “offer” the soap to the king. The float doesn’t continue to rise because its movement is limited by the ceiling of the lower chamber. The water continues to rise to the upper chamber, so the second float begins to rise. His rod is shorter and triggers the second mechanical slave just before the water end. When the second slave moves forward, it opens the right door and offers a towel.

 

Automaton  (self-operating machine) magic

Automaton (plural automata) were not invented by al-Jazari. We know of automata in ancient Greece (Greek: αὐτόματον “acting of one’s own will”). The automata were used in temples and as accessories in the Greek theatre.  The first engineering text that I am aware of is by Hero of Alexandria, a mathematician, engineer, and scientist from the 1st century AD. “Automatopoietica” (αυτoματoπoιητικ ‘ ης) usually translated “on making automatons.” It is reasonable to assume that Hero knew of Aristotle’s “Poetics,” the earliest surviving work focusing on literary theory, in which Aristotle examine the principles behind epic poetry, comedy, and mainly tragedy. We can expand (?)  Poetics as the artistic elements which compose any art form and in our case, the art of automata. Today when we say poetic, we mean an emotional, leary style of expression. I don’t know if this was true in Alexandria, the book is a description of machines that perform “magic” with mechanics or pneumatics, such as automatic door opening in the shrine or statues that pours wine.

Al-Jazari developed and perfected the world of automata. He was the first to employ the camshaft as part of his automata, see the Castel Water Clock or the  Musical Boat [in Hebrew]. He also expanded the use of water flow, smart use of gears, buoys and balancing weights built a long list of automatons, some I already covered, and some I would translate from Hebrew in the near future.

The 18th century was the golden age of automatons. Most of them rely on the camshaft quite similar to the work by al-Jazari. It’s hard to choose between the many exotic examples. I can’t ignore the “Digesting Duck”  (Canard Digérateur) built by Jacques de Vaucanson. The Duck was the size of a living duck and was covered in perforated gold-plated copper to allow a view of the inside workings. It moved like a duck, wiggling its beak in the water, quacking, and most famously though, it could eat pellets offered to it, and then poop them. De Vaucanson claimed that duck contained a small “chemical laboratory” capable of breaking down the wheat grain. In the 19th century, it was found that Vaucanson had faked the mechanism, and the Duck’s poop consisted of pre-prepared breadcrumb pellets, dyed green.

An American artist’s (mistaken) drawing of the Digesting Duck.

I particularly like the automaton of Maillardet, also known (by error) as “Maelzel’s Juvenile Artist.” This is an automaton that can draw four different drawings and write in calligraphy three poems which, among other things, revealed the true creator, Maillardet, in contrast to its wrong reference to Maelzel. The full story appears in this video:

It is impossible to ignore that the eighteenth century is the age Romanticism (also known as the Romantic era), an artistic, literary, musical and intellectual movement originated in Europe. For example in a Hoffman story “The Nutcracker and the Mouse King” Mr. Drosselmeyer, who is a clockmaker and inventor, made a splendid gift for the children: a clockwork castle with mechanical people moving about. Also Olympia, in Der Sandmann (The Sand-man), the life-size mechanical doll with which Nathanael falls disastrously in love. Nili Mirsky in the epilog to “The Golden Pot and other stories “writes about chronic dualism: In the day a strict Prussian judge and in the night a romantic poet or the tension between the occult world and what is exposed in his stories. I suggest adding the tension between the mechanical doll and living humans.

The methods invented to refine mechanical dolls laid the basis for modern technologies, not only for robotics. For example, Edmund Cartwright patented the power loom in 1784, key development in the industrialization of weaving after a visit to “The Turk,” a mechanical doll who played chess and then proved to be a hoax. The mechanical part was real, but there was a concealed man who computed the chess moves. Cartwright wrote: “it is more difficult to construct a machine that shall weave than one which shall make all the variety of moves required in that complicated game?”. Thomas Edison incorporated the camshaft of al-Jazari or Maillardet with the music box and created the phonograph, the first device that allowed recording of music or voices. In general, there are many more examples of a drift of the technology from the “useless” world of automatons to the “practical” world, but I want to talk about the source of the magic.

The automaton is a mechanical doll who moves around and does things that are reserved only to living beings. I don’t think the automata maker confused themselves with the all-mighty creator. There is no mysticism or black magic in mechanical dolls, but there is small magic or amazement in the gap between the mechanical system and human behavior.  Allegedly this magic should disappear in the modern world. Drawing and writing poems are relatively simple tasks for a LEGO robot, which is only a toy. At MIT-Laboratory researcher investigate energy-efficiency in legged robots and created a mechanical “Cheetah” that goes far beyond any dream of makers in previous centuries. I am the last person who wants to reduce the wonder from the Cheetah but the kids watching the contemporary robot do not have the amazed face of the kids watching  “Maelzel’s Juvenile Artist.”  was the charm preserved? Why? I think magic is different. The observer in the thirteenth century and the eighteenth-century lived-in a world with a lot less technology and understood the world around him in a way that we lost. We live in a world saturated with technology and used to not understand most of it, even if we have a technological education. The cell phone in our hands is a powerful computer. Hundreds of engineers from various disciplines, electrical engineer, material engineers, chemists, and a solid-state physicist were needed to produce the microprocessor alone. I doubt that there is one person in Apple or Samsung that knows all the details of the microprocessor, and this is before we even discuss the touch screen or the antenna. We live (well!) with our lack of understanding and content with using it without knowing “the details.” In the 18th century, and before, the automaton was a demonstration of the strength of technology. It allowed René Descartes, the famous French philosopher, mathematician, and scientist to think (fantasize?) that one day the scientific principles at the base of Humans and animals would be revealed, just like we can understand the mechanism of the automaton. This was a challenge to religion and a song of praise to science and its powers. Not every innocent observer is Descartes, but this is the root of our amazement. When we live in a technological world we don’t understand, the astonishment question is very different. Why be astonished more (or less?) by a robot or a cell phone or a game of virtual reality? The magic of the old mechanical dolls is precisely the fact that we can see the technology does its wonders, you can see the gears fit, and the reader (pushrod) moves over the camshaft. We, the eighteenth-century observer and al-Jazari, are, for one moment, in the same place of admiration.

The Peacock Clock and the Beauty of Engineering

Introduction

[This entry was posted more than five years ago in “IR HAOSHER” [in Hebrew] and is the beginning of my journey in the footsteps of al-Jazari, this is an updated version]

Modern machines are designed to be functional, reliable, and inexpensive. No one in the Technion (Israel Institute of Technology) ever talked to me about the beauty of Engineering. Sometimes when I look at a machine or its parts, there is something breathtaking beautiful as art. Can I capture this beauty? What terms should I use? These questions resurface when my friend, Dr. Oved Kedem, retired and I looked for a present for a man who loves science and history of science.

A water clock or clepsydra (from Greek “to steal water”) is a clock where time is measured by the regulated flow of water into or out from a vessel. Water clocks, along with the sundials, are the oldest instruments for measuring time. It is not known when and where they were invented. There is evidence for the use of water clocks in the Middle East, ancient Egypt around the 16th century BC and evidence of early water clocks also in other regions of the world, including India and China. I was looking for an exciting water clock, and so I went on a journey that started at the Weizmann Institute of Science, Through Kafr Qara (كفر قرع), Istanbul and Washington and is still going. I chose to build the water clock of the peacocks.

The Peacock water clock, Topkapi Manuscript,1206

How does it work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in a scoop wheel and a tipping bucket can skip those bits

A drawing of the mechanism with my captions

The clock was built in the wall of a pool with a fountain in the center. The main tank is getting water from the pool, at a rate approximately equal to the water flow to the tipping bucket. I wrote about tipping buckets, for example here and I will do a full mathematical analysis in the future. The latter is the heart of the clock, and when it fills up, once every half an hour, the center of gravity change and the vessel tilt on its axis and discharges its water on the scoop wheel which drives all the clock’s components.  On the copper ball (see diagram above) a peacock made from copper, his tail raised, revolves. The two peacock chicks in the second miḥrāb (محراب)‎) are moving toward each other like they are quarreling. The peahen in the top miḥrāb moves from right to left. The commotion of the peacocks is happening every half an hour, and the glass roundels are colored in red, or lit in the night, to count the passing hours.

The Beauty of Science and Technology

The mechanical drawings by al-Jazari look like Turkish miniatures. My love M.has a treasure chest where she keeps postcards from our travels worldwide, although we have not sent a postcard in ages. When I showed her the Peacock Clock, she searched her collection and found a postcard from our journey to Istanbul twenty years ago, chosen by its merits as a picture without knowing anything about the book or the author.

Despite the narrative break, we should stop here for a moment to contemplate:

A Hidden claim here is that beauty is beauty is beauty. The beauty of the postcard has nothing to to do with the machine and the way it works; it’s just beautiful postcard because of its composition, the colors and other questions for art-lovers. Weizmann Institute “agrees.” In the “Beauty of Science” exhibition, images of experimental results that look beautiful and aesthetic to the eye without any relation to the science behind them. I chose as an example of an image from research by Dr. Einat Vitner. Obviously, the resemblance to Matisse caught the attention of the researcher and the viewers, but I don’t know anything about the scientific significance, or its connection to the elusive concept of beauty in science or engineering.

The Beauty of Science, “Dance of Astrocytes,“ Dr. Einat Vitner, 2011

Is The Peacock Clock beautiful without being a machine?

During my work, I went to Kafr Qara كفر قرع) ) to meet with Dr. Ibrahim Yehia, Director of  TRDC( a Regional Research Center). I wanted to talk to him about his work in the village with active science groups but during the conversation I found, to my surprise, that he got al-Jazari’s book in Arabic, and has a deep interest and knowledge on the subject.  He was a student of Prof. Fuat Sezgin, a professor of History of Science at the Goethe University in Frankfurt, and the founder of both Islam science museums in Frankfurt and Istanbul. The museum exhibits the significant role played by medieval Muslim scientists, inventors, and physicians. Almost all of the items on display are reconstructions of historical instruments and tools that were built by the University of Frankfurt’s Institute of Arabic and Islamic Sciences. Although I am a very rational person with no tendency to mysticism, I thought the way al-Jazari ‘s work permeates into my life is surprising,  a bit strange and attractive. In the same year, I  went to Istanbul to see the Museum. The Museum is located in Gülhane Park which was once part of the garden of Topkapı Palace and is beautiful. It has a beautiful collection of Sextants (navigation) and fascinating maps. Medical instruments from the period in which Islam was at the forefront of science and technology, but the objects designed by al-Jazari seemed like pale folkloristic copies of the book I love:

The elephant clock, right the drawing from the book, left, the model from the Museum.

It can be argued that the Museum artists failed to transfer the two-dimensional beauty of the drawing to a three-dimensional model, but I think there’s a lot more than that. The issue is related to the beauty of machines. Meanwhile, I found out about the exhibition entitled – 1001 Inventions the National Museum in Washington., enter it manually with Sir Ben Kingsley in the role of al-Jazari (a little long ~ 13 min)

The exhibition was launched in 2006 at the Museum of Science and Industry in Manchester and quickly became an international attraction. It was introduced in the British Parliament in London, in the European Parliament in Brussels and the United Nations building in New York. In January 2010 the 1001 Inventions launched at the world-famous London Science Museum to be followed by Istanbul, New York, Dubai, San Francisco and Washington, where I saw it with my son Noah.

The exhibition uses al-Jazari as a role model of technology in the Islamic golden age, with two water clocks: The Elephant water clock and the Scribe water clock. Despite dealing with science and technology, the exhibition is proposing a different narrative: the middle ages are not a dark period in-between the decline of the Roman Empire and the Renaissance, but also the golden age of Islam.  As a result, the items themselves (“elephant clock”, “pumping facility” and so on) are great designs without running water, gears or any working mechanism at all. This is a very decorated but empty shell. Despite the investment, I do not think that none of the objects is even close to original beauty.

I think there is something inside us that identifies and responds to beauty. When it comes to science and engineering, this beauty is related to precision and correctness. In the past seven years, I have taught high school student “computational science,” and it is easy to say a software solution is “beautiful,” and when it is cumbersome and forced. The beauty, in this case, is not purely aesthetic but has to do with simplicity and strength.

Simplicity

To explain the connection between simplicity and beauty, I want to stand on the shoulders of giants. Aristotle believed that the Earth was the center of the universe and the Sun, Moon, planets are attached to transparent, rotating spheres surrounding the Earth. More astronomical observations were difficult to fit in the model and by the time of Ptolemy(2nd century AD),  the model included a system of two spheres per planet: one called its deferent; the other, its epicycle. The final model was so complicated, Alfonso X, king of Castile called the Wise (Spanish: el Sabio) who gained considerable scientific fame based on his deep interest  in astronomy said: “If the Lord Almighty had consulted me before embarking on creation thus, I should have recommended something simpler.”

Picture of the world according to Ptolemy, the most complete and detailed description of the geocentric model following Aristotle

in the evolution of the scientific model of the movement of celestial bodies there are more heroes, Copernicus is perhaps the best known of them all, but I would like jumped straight to Johannes Kepler (1571-1630) who replaced this complicated  system with three simple rules:

  1. Elliptic orbit: The orbit of a planet is an ellipse with the Sun at one of the two foci.
  2. The law of increasing velocity: The planet travels faster when closer to the Sun, and then slower when farther from the Sun. Kepler wrote this law mathematically enabling calculations and predictions.
  3. The harmonic law – The Square of the orbital period (the time it takes for the planet to circle the Sun and we call it “year”) is directly proportional to the cube of the semi-major axis of its orbit.

The summary of Kepler laws is maybe too concise, but I think everyone could see the beauty in the ability to explain the complex movement of the night sky using three simple rules that require mathematics of middle school. The simplicity and elegance of Kepler’s model help us to be convinced but do not make it right. Like any scientific or engineering theory, it should be repeatedly tested and verified. Astronomical observations are numerous and contain deviations and mistakes. The regularity is not simple. Kepler spent many years analyzing the data. As the scientific model consists of simple rules, as the rules explain more phenomena, sometimes seemingly unrelated, there is a sense of logical harmony, echoing within us as more beautiful.

Power

From time to time, there is an engineering achievement, such as the telephone or the electric bulb that makes us truly believe in the power of human invention to improve the lives of humanity. What makes an engineering or scientific solution powerful beyond its success? It tried to look at an example:

The wheel is such an old invention that we have no way of knowing who or where it originated. Depictions of a wheeled vehicle appeared between 3500–3350 BCE in the Bronocice clay from southern Poland. The wheel helps to bridge distances and ease transportation of objects and goods. To my surprise, the benefits of transportation were limited for thousands of years due to a lack of roads and infrastructure.

However the wheel was still used for many purposes, Stone mills powered by water, Distaff and a spinning wheel, pulleys to lift the weight, toothed wheels to change the speed, torque, and direction of a power source which allowed ancient civilizations to create complex machines as al-Jazari demonstrated so gracefully.

The index of power asks how elaborate is the engineering solution and how many layers it includes. I think it’s similar, but different, from the beauty of subtext, when the contents of a book or movie, which was not transferred to us explicitly, becomes understood as the book/movie unfolds. This is not just the complexity, but the integration and the consolidation, The beauty of how the various components fit together; the water fill the tipping bucket carefully designed so that it will tilt every half hour, rotating the scoop wheel, a little bit like our enjoyment of Rube Goldberg’s  machine :

Rube Goldberg self-operating napkin

In this respect, when the machine lost its function and made just a design is losing its power and simplicity, and hence its beauty, even if its shape is intact. With the crew of the workshop of the Clore Science Garden, we built a prototype of the Peacocks Clock:

The fountain that changes its shape and the controversy with the Banu Musa

“Allah has promised the believing men and believing women gardens beneath which rivers flow, wherein they abide eternally.”

Qur’an 9:72

The fountain with two tipping buckets, Topkapi manuscript, 1206

Introduction

The Muslim paradise is called Jannah ( جنّة), literally “garden.”  Every time heaven is mentioned in the holy book of Qur’an, there is a description of flowing water and fruit-bearing trees. This is not surprising because Islam came from the desert, hot and arid lands. I would like to ignore the other attributes of al-Jannah such as houris; splendid companions of equal age, lovely eyed and virgins, who will accompany the faithful. My only focus is on the scenery. Like Garden of Eden in the Bible, there are four rivers in Jannah, the Euphrates flows according to both books, but the other rivers are different, and they have a common source named Salsabil (سلسبيل).

Gardens were significant to Islam from its inception. The garden landscaping has a spiritual meaning which exceeds the human need for shade and water. They are perceived as a place of rest and contemplation, an earthly equivalent to life in heaven. This metaphor reached its peak in Chahar-bagh, (چهارباغ), in which the garden was divided into four parts by water channels; the four water channels being the four rivers of paradise with a fountain in the center of a pool, representing Salsabil. I think that al-Jazari’s deep interest in fountains is related to the importance of gardens in Islam. 

A miniature of paradise from the 16th century

How does the fountain work?

The fountain of al-Jazari is installed in a pool. For an hour the fountain shoots up from the main orifice and then for one hour it emits six curving jets from six nozzles, and the process repeats itself. Today it is a trivial task for any engineer, but in the 12th century, with no electronics or electric valves, it was almost a miracle. The technical explanation, as always, will be colored in blue, so anyone who is not interested in early control systems can skip those bits.

At some distance from the pool, al-Jazari built a high house into which the water flowed. This section does not appear in the drawing. The water from the high house flew into the copper bowl welded to a pipe with four openings. This is the same drawing as above, but with my captions.

At the bottom of the titling pipe, al-Jazari welded a ring which is seated on an axle so that the pipe is like a kids seesaw. The right side is slightly heavier, and therefore it tilts to the right, and the water comes from both openings on the right. The main opening fills the tank and the narrow pipe which shoots the water up in the air. The secondary opening is much smaller, and it slowly fills the tipping bucket (in red). In the drawing, the tipping bucket is almost full. After one hour, the weight of the water at the front-end is heavy enough to make the tipping bucket swing, and the black rod will push the tilting pipe upward so the seesaw would tilt to the left and water fill the other tank, the wide pipe around the narrow pipe and comes out in six jets. The process repeats itself.

Banū Mūsā

Al-Jazari opens the fourth Category “On fountains which change their shapes at known intervals and on perpetual flutes” with a brief statement:

“I did not follow the system of the Banū Mūsā, may God have mercy upon them, who in earlier times distinguished themselves in the matters covered by these subjects.”

The Banū Mūsā brothers are the predecessors of al-Jazari and are important to understanding his work. Banū Mūsā, the sons of Moses, is the name shared by three scholars, brothers from the ninth-century, sons of Mūsā ibn Shākir, a Persian astronomer. At a young age, they join the famous House of Wisdom, a library and a translation center in Baghdad. It is known that the brothers wrote together more than 20 books, but most have been lost over the years. Their most famous book and only two copies survived is The Book of Ingenious Devices (كتاب الحيل Kitab al-Hiyal( which al-Jazari is referring. The book was commissioned by the Abbasid Caliph of Baghdad, Abu Jafar al-Ma’mun ibn Harun (786–833), who instructed the Banu Musa to acquire all of the Hellenistic texts that had been preserved during the decline and fall of Roman civilization. This rescue operation has cultural importance, which exceeds by far the current post. Some of the devices described in their Book were inspired by the works of Hero of Alexandria and Philo of Byzantium, as well as ancient Persian, Chinese, and Indian engineering. However, many of the other devices described in the book were original inventions by the Banu Musa brothers. Donald Hill, who translated this book, as well as al-Jazari’s book, wrote:

“The Banu Musa went “well beyond anything achieved by Hero or Philo.” Their preoccupation with automatic controls distinguishes them from their Greek predecessors, including the “use of self-operating valves, timing devices, delay systems, and other concepts of great ingenuity.”

The book describes the construction of 100 devices, including seven automatic fountains.

What is the Controversy?

Al-Jazari did not specify which fountain he is referring to, but he did write:

“They made the alternation [fountain water shapes] with vanes turned by wind or by water so that the fountains were changed at every rotation, but this is too short an interval for the change to appear [to the full effect]. Then in two designs they used a pipe like an almost horizontal balance arm. The water flowed through it …”

It is clear that this is the fountain he is referring to:

A fountain that alternates water shapes by use of a balance from
The Self Changing Fountain of Banu Musa bin Shakir by Prof. Salim T S Al-Hassani

He concludes: ” I do not know whence this confusion [came], from the original or from the copy.”

For those who really want to dive into the details, you can see here the fountains the Banu Musa. There could be no argument that al-Jazari borrowed key concepts from the Banu Musa, including the placement of a narrow pipe within a wide pipe, the concept of two water tanks and variable feeding with time. His main disagreement is over the control method. In his opinion, the intervals were too short, and the result could be erratic. He’s probably right. Al-Jazari explains what’s wrong with the design, but the details are of little importance. The technology changed so dramatically that the historical techniques to control the timing are only an odd puzzle of how we can control timing before we had, electronics and electric valves. However, curiosity and skepticism are the best guides for every engineer today, just like eight centuries ago.

Curiosity and Doubts

Anybody who taught high school or Bachelor’s degree in science or technology knows that academic success is no guarantee for curiosity, healthy doubts, or critical thinking in general. Excellent students can answer the questions in the exam but find it difficult to ask questions about a scientific paper or engineering presentation, to test if the assumptions are robust and can stand rigorous evaluation, if there is an alternative explanation or if there can be another model. Many excellent and feel uncomfortable with the new requirements so different from their previous experience in school. In parenthesis, as an educator, I have to say that this is not a decree of fate and schools can do a lot, but that’s another discussion. My encounter with al–Jazari is limited to his book, but beyond is high of engineering capabilities, it is clear he was curious and had a healthy measure of inquisitiveness and skepticism. He checked the water regulator attributed to Archimedes and found it insufficient, he read the Banu Musa and had his doubts regarding the control method. Beyond the benefit of the healthy engineering skepticism, as he adds question marks, I like him more.

 

The pump and the Crankshaft

Introduction

The fourth machine for raising water is a pump based on a slider-crank mechanism. A more detailed explanation about crank, its history, and why is it interesting will follow. Since the drawing by al-Jazari is difficult to understand, I will present the revised drawing by Dr. Donald R. Hill, The book translator, and annotator. This is a good opportunity to write a few words about Hill, who was instrumental in bringing this book to us and in understanding al-Jazari and his importance to the history of Engineering.

Machine for raising water from a pool, Chester Beatty Library in Dublin probably 15th century from Iran or Iraq

Donald Rutledge Hill (1922-1994)

Hill was born in London. He joined the English army engineering unit during World War II until he was wounded in action in Italy. Back in England, he studied Engineering at the London University, obtaining his engineering degree in1949. He later worked for the Iraq Petroleum Company in Lebanon, Syria, and Qatar. Hill was gifted in languages, and before arriving at the Middle East, he was already fluent in French, German, Spanish and Italian. The move allowed him to add spoken Arabic but also to master literary Arabic. In 1964 he completed an M.Litt in the history of Islam and 1970 a Ph.D. from the University of London. His impressive accomplishments are a result of the unique combination of engineering knowledge and mastery of Arabic as well as Orientalism at its best, the study of the Arabic culture rather than a romantic perception or in contrast to the West. His main contributions are the translations of “The Book of Knowledge of Ingenious Mechanical Devices,” by al-Jazari, which is the sole purpose of this blog. He also translated the “Banu Musa” mentioned here more than once, and “On the Construction of Water Clocks” attributed to Archimedes. His contribution far exceeds the traditional role of a translator and includes annotations, drawings and writing several books on the history of engineering and technology that helped reinstate the technology in the golden age of Islam to its proper place.

How does it work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in Cranks (Are you series? Without Cranks we would not have locomotives or cars!) Or toothed wheels can skip those bits

An ox, in the upper room, is rotating the system. If you are confused after the fake cow, in the previous post, this is an actual animal, and without it, the pump would not work. The part of the gears and the conversion of the rotary movement to a linear one is difficult to understand (for me and others), and it looks like al-Jazari drawing is in error. I bring side by side the original illustration by al-Jazari and the drawing by Hill, and I added captions.

Combined drawing, al-Jazari, and Hill

The Ox, in the top room, rotates the horizontal tooth-wheel, which in turn rotates a vertical tooth-wheel, much like the classic sāqīya already explained here. The difference is that the vertical tooth wheel is attached to a slider-crank. We met this mechanism in the water wheel pump where it converted circular motion to linear motion and possibly vice versa. This is an essential component in engines and pumps till this very day. This is an animation of the pump, and you can see the slider-crank mechanism clearly:

It is easy to see that when the wheel rotates the crank moves within the slot and since the ladle is anchored at the axle it will raise the water and empty them later. In al-Jazari drawing( in contrast to the text which is quite clear) it seems that the vertical tooth-wheel is in 900 and the crank is in an odd angle relative to the slot. Hill’s drawing is correcting all these problems and explains well how it worked. Large engines are usually multicylinder to reduce pulsations from individual firing strokes, with more than one piston attached to a complex crankshaft:

Flat-plane crankshaft (red), pistons (gray) in their cylinders (blue), and flywheel (black)

Crankshaft

Many internet sites consider the crank as an invention of al-Jazari, for example here:

“In 1206, al-Jazari invented an early crankshaft, which he incorporated with a crank-connecting rod mechanism in his twin-cylinder pump. Like the modern crankshaft, al-Jazari’s device consisted of a wheel setting several crankpins into motion, with the wheel’s motion being circular and the pins moving back-and-forth in a straight line. The crankshaft described by al-Jazari transforms continuous rotary motion into linear reciprocating motion and is central to modern types of machinery such as the steam engine, internal combustion engine, and automatic controls. “

Before I expand a little on the evolution of the crank, it is important to note that the concept of an individual inventor is, in most cases, excessive romanticizing. It is inordinate when we have a definite inventor and more so for the Middle Ages or before that.  Take, for example, James Watt, who invented the steam engine in 1769 and issued a patent for it. A few children’s books suggest the idea of the steam engine came at the age of 12 while young James sat in the kitchen with his aunt, staring at a teakettle. The water was boiling so hard that the lid of the tea kettle began to jump up and down. This is simply not true. Watt invented the steam engine while fixing Newcomen’s steam engine for the University of Glasgow. This engine was invented in 1712 and was considered a great success. More than 100 such engines were installed as water pumps in mines in England and Wales. Also, the Newcomen engine is not the first steam engine, and there are predecessors from the 16th and 17th centuries. Don’t get me wrong, James Watt is entirely worthy of his glory, his improvements (the separate steam condenser and later the double-action engine) were very significant and the industrial revolution, for better or worse, is the consequence of the improvements by Watt.

The electric light bulb was invented by Edison, and the airplane was invented by the Wright brothers, but their story is not very different from the story of James Watt. Without diminishing their impotent contributions, their inventions, just like Watt’s steam engine, are a link in a long chain.

Manual cranks appeared in China during the Han dynasty (202 BC-220 AD), and we find ceramic models in the tombs of the period. However, the potential of the crank of converting circular motion into reciprocal motion never seems to have been fully realized in China. There are manual cranks examples from Europe and the Middle East. For example this picture of Roman iron crank for an unknown purpose from the 2nd century AD

roman crank

A Roman iron crank dating to the 2nd century AD was excavated in Augusta Raurica, Switzerland.

The crank appears in the book by the Banu Musa from the 9th century, which al-Jazari new and quoted. However, in their version, the crank did only a partial rotation which wouldn’t allow for significant power transfer.  Al-Jazari did not write, as he did in his fountain [in Hebrew], for example, that he looked at design by the Banu Musa and decided that it requires improvement and does not refer to the originality of his design.

330px-Steam_engine_in_action

Steam Engine, Wikipedia

What is so beautiful about this door? (Cast brass door for the Artuqid Palace in Diyarbakir)

Introduction

The sixth and final category in the book contains five dissimilar designs. The first and most grand of all is the Artuqids Palace door in Diyarbakir, Eastern Anatolia. Al-Jazari opens this chapter with some enthusiastic message very unusual for him:

It is the masterpiece; to view it saddles are strapped on. Truly it is the pearl, the orphan, a priceless possession.”

This passionate text surprised me because this door, engineering speaking, is quite simple and doesn’t contain the inventions and surprises included in most of al-Jazari works. The beauty is not in engineering, but in the art and the craft. Donald Hill, translator, and interpreter of the book, Engineer by heart, was interested mainly in the casting technology: “Of particular importance, also, is the first unequivocal description of metal casting in closed mould-boxes with green sand, a method not used in the West until the end of the fifteenth century.” Casting is a manufacturing process in which a liquid metal (al-Jazari used copper, brass, and bronze) is poured into a mold with the desired shape. “Green” sand is used even today. The name is a bit confusing as the sand is not green color at all. Instead, the sand is called “green” because it is “wet” sand, which contains water and organic bonding compounds much like we say “green wood” in carpentry.

I have two very different questions:

  • Sorry, what is so beautiful about this door? Or at least why al-Jazari admired his work?
  • How is it possible that military considerations are not part of the design? What does it say about al-Jazari as an engineer?

Description of the door and its beauty

It is a door with two leaves which rise to the height of about four and a half meters (originally 18 spans ( شِبْر) ) and the width of each leave is a meter and a half.

The Palace door, Topkapi Manuscript, 1206

The Palace door, Topkapi Manuscript, 1206

In the center of each leave, there is a complex geometric pattern that includes Hexagram (Star of David) and Octagram. It is interesting to note that both these shapes belong to the family of Magic stars. A magic star is a star polygon in which numbers are placed at each of the n vertices and n intersections, such that the four numbers on each line sum to the same magic constant: M=4n+2. The solutions I know to magic stars are only from the 20th century, but the use of the two was very common in the Muslim world. Is it possible that al-Jazari sensed mathematical beauty without knowing the math?

Since it is a relatively complicated pattern, I colored the drawing to see Magic Stars:

Islamic art makes frequent use of geometric patterns which were developed over the centuries. There is  “artistic unity” across time and place. I bring three pictures of three doors with different geographical, cultural and historical background, both Shi’ite and Sunni Islam

The left door is a Turkish door from the14th-century. The middle door is a Grand Palace in Fez in Morocco from the 13th-century. The wooden door from Iran on the right is not dated.

The Islamic aesthetic shift toward complex geometric structures is attributed to the prohibition in the Qur’an of figurative images to avoid becoming objects of worship. Geometric structures are abstract, emphasized symmetries, and suggested infinity and therefore reminding Muslims the idea of the infinite nature of Allah. This explanation does not satisfy me since the second commandment :

” Thou shalt not make unto thee any graven image or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth. Thou shalt not bow down thyself to them, nor serve them”

Did not yield a similar tradition in Jewish art. I don’t see anything that would justify the special enthusiasm from the geometric patterns of al-Jazari. However, if any of my readers find some special beauty or a hidden message, please comment as I would love to learn.

The pattern was bounded by brass plates a which carried Kufic((كوفي ) inscriptions and leaf motif decorations. This reads “the dominion is God’s, the One, the Conqueror”

Kufic is the oldest calligraphic form of the various Arabic scripts. Kufic developed around the end of the 7th century in Kufa, Iraq, from which it takes its name, and other centers. Kufic was prevalent in manuscripts from the 7th to 10th centuries. In the late 12th century, when the door was made, it was less used, and I do not know if this choice has a special meaning?

The calligraphy is surrounded by  bronze plates which were decorated with red copper leaves:

The process is relatively complex; firstly, he casted bronze panels. Using a scalpel, he carved the leaf template and poured melted red copper.

In the drawing, there are no brass domes, but in the text, there is a detailed explanation and diagram of a dome. I took the liberty to add this to the original drawing by al-Jazari:

I did not cover every detail, but I cannot ignore the door’s knockers from cast brass in the shape of two connected serpents, their heads facing each other. Their mouths are open as if they wished to devour the lion between them.   The door did not survive (I am convinced it was built, and not just designed, because of the richness and the details in the text). It is interesting to note that very similar Bronze door-knockers from the Great Mosque in Cizre are now in the Museum of Turkish and Islamic Arts in Istanbul. To my surprise, pretty similar versions have found their way to Copenhagen and Berlin museums.

We will never know what caused al-Jazari to be that happy with this door. Maybe he enjoyed his geometric patterns and thought particularly beautiful, Maybe He enjoyed his success in the complex casting or his work with various metals, brass, copper, and silver, maybe he was happy the amount and richness of the details and possibly it was a combination of all.

 

Military engineers and engineering history

Engineering has existed since ancient times, the invention of a pulley, the construction of the Egyptian pyramids or the copper production process are all “Engineering” according to all modern definitions but only in the 14th century was the first use of the term engine’er. The origin of the word is from Latin words “in generare” meaning “to create” but relating to the designing or creating engines of war like the catapult or assault towers. For many years all the engineers were military engineers. Archimedes, a gifted mathematician and scientist had a major role in the Second Punic War. He improved the power and accuracy of the Catapult, He designed a giant claw to destroy Roman ships, and the peak of his inventions was burning the Roman fleet using mirrors.  Leonardo da Vinci engineering career included military chapters as evident from his letter to Ludovico Sforza, ruler of Milan. He wrote:

“I have plans for very light, strong and easily portable bridges with which to pursue and, on some occasions, flee the enemy.. Also, if one cannot, when besieging a terrain, proceed by bombardment either because of the height of the glacis or the strength of its situation and location, I have methods for destroying every fortress.”

The Faculty of engineering at the Technion is still called “civil engineering,” to be separated from military engineering, although the former has become almost a non-issue in the modern world of engineering.

It is somewhat surprising that there is no military engineering chapter al-Jazari’s work and even when he builds the door for the Palace, no considerations of strength or defense capability are mentioned, not even a single word. Two possible explanations:

  1. The principality in Diyarbakir was so peaceful that there was no need for a military engineer.
  2. The expectations from the Court engineer in Diyarbakir were different.

 

A change in Diyarbakir and al-Jazari as an “engineering magician.”

The dynasty was founded by Artuk Bey, a general under the Seljuq emir of Damascus. In 1086 he was appointed the governor of Jerusalem, a surprising twist to a story about a Muslim dynasty which ruled in Diyarbakir Anatolia. We need to remember that the Middle East map in the 11th and 12th centuries is very different from the map we know today. After Artuk death in 1091 his sons, Sökmen and Ilghazi were expelled from Jerusalem by the Fatimid vizier and set themselves up in Diyarbakır and Mardin in Anatolia.

This door was installed at the Artuqid Palace in Diyarbakir where al-Jazari was the court engineer. The Palace was built within the walls of Diyarbakir during the reign of Salih Nasreddin Mahmud (1200-1222) Artuqid king who employed al-Jazari like his father and brother before him. The Palace was excavated in the 1960s, but most of it is still buried under the mound, and I have a fantasy that the site will be excavated a second time and we will find some of the remains of al-Jazari’s work. In the 12th century, there were a few battles with the Crusaders, with Georgia and clashes of within the Muslims. I don’t think a peaceful period is the explanation of the absence of the military aspect in al-Jazari’s work.

The Artuqids are a Turkmen dynasty which started as a warrior tribe, and its original power was military. In the 12th century, they were settling in the old cities of Amida (the previous name Diyarbakir ) and Mardin. These are ancient cities with urban culture since the Assyrians. The population is diverse and includes veteran Christian and newcomer Turkmen population as well as other migrants from Iran and other places that continued through the 13th century. Beyond the monumental Al- Jazari book, there was probably a workshop for copying and illustrating manuscripts. Rachel Ward identified two other illuminated manuscripts that were produced there. There were new architectural designs, Sharon Talmor as part of her graduate work at the University of Tel Aviv found three which mark a new era in Islamic architecture. As a part of the assimilation of a warrior tribe into the urban setting, there was probably a need for a change, and there was a thirst for cultural and artistic activities. I’d love to hear other suggestions too, but this is a possible explanation for the absence of military engineering.

So the circle closes. The question of the beauty of the door is connected to the role of al-Jazari. As we step into the book, I think we will be more convinced of his role as  “a magician of engineering”  the man who harness science and technology to create and beauty and astonishment.

 

The Pump with the Fake Cow

Introduction

The third raising water machine described by al-Jazari is clearly an attraction in the King Palace and not a solution to irrigation problems in Diyarbakir. It’s not just the fake cow(!) made of wood, and I will elaborate on this later on, but the text speaks for itself:

“[The one described here] is beautiful to behold, with upper wheels, splendid craftsmanship, elegant shapes, and handsome design. The ropes are silken, the jars delicate and painted with various colors, as are the wheels, the cow and the disc.”

In this respect, he reinforces the concept of the palace Engineer as a “magician.” I wrote about this briefly here [in Hebrew], and I will use the third pump to expand. This design is based on the saqiya (Arabic ساقية‎‎), an ancient device for raising water that can still be seen today. In the following paragraphs, I will explain the saqiya and the similarities and differences from al-Jazari’s pump.

The third water raising device, 13th-century manuscript, SÜLEYMANIYE LIBRARY, Istanbul

How does it work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in Scoop wheel or Sindi wheel can skip those bits

Al-Jazari device is relatively complex, and only the top part is visible to the observer. This is the original drawing by al-Jazari with my captions:

The center of the device is a square pool with a bottom copper plate, and its sides made of marble. The water flows into the pool and down through an opening on a scoop wheel which is hidden in a chamber below the pool, not visible to the observer. The scoop wheel rotates toothed wheels that transmit the movement to a vertical axle. The axle is hidden within a copper pillar with a copper disc. A wooden cow is standing hairsbreadth above the disk, light as possible and supported by a wooden rod attached to the axle. In this way, it looks like the cow is operating the traditional saqiya. (Pictures and explanations of the saqiya will follow).Toothed wheels turn the Sindi wheel which has the jars on it. Thus raising the water and dispenses the water into the irrigation system of the Palace’s garden (not in the drawing).

It is interesting to note that al-Jazari calls the wheel of the Saqiya “Sindi wheel,” Sindh is in the western corner of South Asia, bordering the Iranian plateau in the west, today in Pakistan. So at least in his time, it was assumed that this is the “origin” of the saqiya.

 sāqīya (ساقية)‎ 

A Photograph from Spain of a Saqiya, Wikipedia

This was the most effective device for raising water used from Spain in the West to India in the East at least from Roman times to the insertion of motorized pumps. An animal (Ox or a donkey) turns a horizontal wheel, which is engaged with the vertical wheel and so causes it to turn. This causes the belt of buckets or jars to circulate and lift water from the well or the stream.  There is no knowledge about the origin of the device. Some claim it was ancient Egypt, 4th century BC, some claim Persia and al-Jazari, and his contemporaries thought Sindh. Regardless of the history, it was very common throughout the Muslim world during the middle ages.

There are many testimonies to the early saqiya here in Israel. The most ancient one in Tel Dor. A saqiya also appears in “The Picturesque Palestine” published in the early 1880s by Charles William Wilson:

The Saqiya is five times more efficient than the Shaduf, which was explained here. It can pump 10-25 cubic meters of water per hour. The unusual version of al-Jazari did not use animal power but water energy. The use of water power for pumping and industrial use, for instance, in the paper industry was known at the time of al-Jazari. The most common device was Noria(ناعورة), which consists of a large water wheel of wooden containers, as shown in the photograph below:

Three norias of Hama on the Orontes River in Syria. Originally to irrigate the City Gardens and now a tourist attraction.

Al-Jazari did not use the noria but the scoop wheel, I may write on this choice in the future. I am more intrigued by the wooden cow.

 Why a wooden cow? Or the engineer as a Magician

The wooden cow of al-Jazari contradicts all engineering logic. First of all, it has no contribution to the water raising secondly it loads the pump and reduces its efficiency. Funny that Wikipedia writer wrote:

“A manuscript by Ismail al-Jazari featured an intricate device based on a saqiya, powered in part by the pull of an ox walking on the roof of an upper-level reservoir, but also by water falling onto the spoon-shaped pallets of a water wheel placed in a lower-level reservoir.

An observer in the 12th century would not make this mistake. The dimensions of the wooden cow are not specified, but the copper disc is about two spans or ~ a half meter. The central axle that connects all the toothed wheels is 12 spans or approximately 3 meters. Even if the image isn’t to scale, it is obvious that the cow was a decoration and was not intended to mislead the observer. Why al-Jazari did this?

My love, M.  thinks it is the handicap principle. The handicap principle is a hypothesis originally proposed in 1975 by Israeli biologist Amotz Zahavi with his wife Avishag Zahavi to explain strange phenomena in nature. Their book is called “peacocks, altruism, and handicap principle” (in Hebrew). The amazing colorful peacock’s tail requires physiological resources to build and maintain, attracts the attention of predators, and hinders the peacock’s ability to escape. At the same time the heavy tail signal peahens that the peacock is very sure of himself and has an impressive set of genes, thus improving his chance to find a spouse. In some paradoxical way, the colorful tail of the Peacock also manages to deter potential predators. In the 1970s, there was broad opposition to the handicap principle because it contradicts the principles of evolution, but today it is widely accepted. Did al-Jazari want to show that an unneeded wooden cow doesn’t bother him to raise water with joy?

I prefer another explanation. We perceive engineers as professionals who analyze data to design and build machines, structures, or materials to achieve the objectives, taking into account the product requirements and limitations, including regulations, cost, safety and more. Al-Jazari was working in a different environment with far fewer limitations and no regulation at all, but his concept of engineering and his role were different. Engineers are hiding mechanisms for any number of reasons, but why Al-Jazari chose to hide the mechanism? Did the tiny wooden cow stress the lack of the usual animal in the saqiya?

I suggest that in al-Jazari’s perception, the engineer is a little bit a magician. It is certainly true for the Magic Pitcher or some of the automata, and it is true for this pump. The hidden mechanism and wooden cow are used to make the riddle more intriguing. It makes no sense to ask a magician about the efficiency of his act, and likewise, there is no sense to ask Al-Jazari why a cow? His goal was not an effective pump, but the wonder of the beholders. Elly Truitt wrote an interesting book called “Medieval Robots” about the transition of Western Europe between the perception of automata as magical to science and technology approach. Truitt tells of a 12th-century book “Chansons de geste, le Voyage de Charlemagne” (Songs of Deeds, the travels of  Charles the Great”). The story is about the visit of Charlemagne to King Hugo’s court in Constantinople. Charlemagne and his barons were astonished by an automaton of a rotating palace mimic the circular motion of the celestial sphere. When the west wind blew the Palace turn, and two copper children blew their ivory horns with heavenly music. Charles’s court thought that this automaton was so expressive that they would have believed they were actually alive. Charles and his barons were unfamiliar with the technology, lost their footing once the palace began to turn. This story is fictional. Charlemagne didn’t make this expedition to Jerusalem and didn’t stop in Constantinople on his way. It is true that there were remarkable automata in the courtyard of Byzantium in the 9th century and a people from the west who had no technological know-how, thought that magic and sorcery are involved. Al-Jazari is the magician but with no magic but hidden scoop wheel and clever use of toothed wheels.

 

Two Scribes and Bloodletting

Introduction

This is the second basin of al-Jazari for blood-letting, “from which the quantity of blood which it holds can be ascertained.” Its mechanism is almost identical to “The Basin of Monk,” explained here with some additional background on the history of bloodletting. The main difference is in the design; two scribes are sitting on a raised platform, one writer rotates, and his pen indicates the amount of blood collected in the same manner as the monk. The other scribe has a writing pad that rises so that his pen, which does not move, indicates the amount of blood. We have plenty of information, medical and images which documented bloodletting. There is no precursor bloodletting tool before al-Jazari and all bloodletting tools after his time are simply bowls with marking. And the question is why?

The basin of the two scribes. Detached folio from a Manuscript,1315

How Does it work?

The mechanism is almost identical to the basin of Monk. The differences are so tiny, if the readers are interested in them, he or she probably do not need my mediation. Still, for the comfort of my readers, I provide my adaptation of the modern drawing by Donnell Hill, the book translator and annotator. If there are any errors, the responsibility is all mine. The technical explanation, as always, will be colored in blue, so anyone who is not interested in pulleys or balancing weight can skip those bits.

Both scribes are sitting on an elevated platform on four columns. The scribe to the left sits on the main pulley and is holding a pen which is an indication of the amount of blood collected so far. Two ropes are connected to the main pulley through the hollow columns and two small pulleys. At one end there is a float, and the other end has a balancing weight. The ropes are tight before the beginning of the bloodletting, and the pen is indicating zero. The blood goes to the basin and the drain and is collected in the container where the float is located. As a result, the float goes up and release rope through the pulley, the weight continues to pull down, and the main pulley with the scribe on it would rotate. The float is also connected to a rod with a writing pad at the end. As the amount of blood accumulates, the writing pad will rise as well. The fixed pen in the hand of the second scribe would also indicate the amount of the blood.

 

Bloodletting tools throughout history

I don’t know if there are any other medical procedure as bloodletting that got so many medical or artistic expression. This is just a small sample:

Pictures from right to left:

  • A drawing of bloodletting on a Greek vase from the fifth century BC
  • A Bowl with a scene of bloodletting from Iran, the first half of the 13th century, Islamic Art Museum, Berlin.
  • Caricature of bloodletting by James Gillray, 1804.

Pictures from right to left:

  •  A Physician is letting blood, 13 century, Aldobrandino of Siena. British Library, London.
  •  A surgeon binding up a woman’s arm after bloodletting. Oil painting by Jacob Toorenvliet, 1666.
  • Photo of bloodletting from 1860, one of three known photographs of the procedure.

In all these photos and many others, the blood is collected in a bowl.  In 1979 the Smithsonian Museum published an impressive catalog of bloodletting tools. The catalog is available online and is full of great information including an article summarizing the topic and plenty of images of bloodletting instruments; there is nothing more than a bowl with graduated marking:

Bleeding bowl with graduated markings to measure the amount of blood. Made by John Foster of London after 1740.

How do we explain al-Jazari choice?

Quite a bit of al-Jazari work relies on his predecessors. Al-Jazari himself was the first one to reference previous scholars as I showed in the Castle Clock or in The Fountain of the Two Tipping Buckets (in Hebrew). Sometimes the technological leap forward is very large, for example, water wheel pump and sometimes less significant as in all the fountains. But not only that there is no precedent to al-Jazari’s designed for measuring blood there is no ” sequel”; no one used al-Jazari ideas. It is worth mentioning his book was quite popular; there are not many manuscripts from the 12th century with 15 remaining copies and bloodletting continued for about 700 more years.

Surprising?  Maybe not. Al-Jazari solution is complicated and requires a lot of work. There is no comparison between the serial production of a ceramic bowl even in the 12th century, and fine mechanics. The materials are more expansive, the basin is made out of brass, and the scribes are made of copper. All this raised the final cost. Also, al-Jazari’s solution is much more difficult to clean and maintain, and offers only one clear advantage: it is more fun and allows the patient to track the amount of blood easily.

I have no evidence in the text, but I am convinced that al-Jazari understood the cost of material, the amount of work and the complexity of maintenance as well as I do. So why did he chose as he did? I have two proposals, and you are welcome to offer your own.

  1. I discussed this question with my young son. He said that if I were asking him in sixth grade to invent a tool that measures the amount of blood during bloodletting, he would look for a solution like this (he added a lot of limitations due to what he knew at that time) because it’s much more “cool.” Al-Jazari was an engineer serving in the Palace in Diyarbakir. The cost was no consideration for his employers, and there was no shortage of servants and slaves. However, his love for automatons constantly sought surprising solutions to the problems around him. This combination of an engineer “crazy” for automatons without constraints won’t be back.
  2. My love M. turned my attention to the Linguist Roman Jakobson and his much-cited article “Linguistics and Poetics” which maps the language to its essential function. For example, The referential function corresponds to the factor of Context, and its role is to transmit information. Some say that this is the main function. I want to focus on the poetic function; it focuses on the message himself, rather than the addresser (sender) or addressee. I took the liberty to take a post of her (in Hebrew) “One Great Illustration and Ora Eitan” and modify it slightly:

“According to the linguist Roman Jakobson” The primary intent of the message as such [in our case, the message is the automaton itself, the way it fulfills its purpose. AG] is the poetic function of language. In Jakobson words: The set (Einstellung) toward the message as such, focus on the message for its own sake, is the POETIC function of language.”

In these terms, al-Jazari is a poet or at least a poet of automata.  In this respect, the discussion on price or maintenance misses the point completely because it treats poetry with traditional engineering tools.