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


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


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


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.

Two Automatons and Iconoclasm


Two automatons, an automaton of a man holding a goblet and a bottle and an automaton of two shaykhs upon a dais, are very similar in their mechanism but also, unfortunately, similar because all the faces of the characters were damaged (thanks to Galia Levy-Grad who brought this to my attention) more on this topic below:

An automaton of a man holding a goblet and a bottle on the right, and an automaton of are two shaykhs upon a dais, on the left. 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 tipping bucket or a siphon can skip those bits.

Both automatons have very partial drawings. Donald Hill, the book translator, did not add a modern schematics as he did with most machines in the book. The reason is Al-Jazari own words: “construction of the figure was described in the previous chapter [here] so there is no need to explain it.” This is my drawing, based on the text and previous drawings:

The mechanism of a man holding a goblet and a bottle

This is a mechanical slave made of copper; the head and neck are a wine reservoir slowly dripping into a tipping bucket. The tipping bucket is partially hidden by his hand. You can see a tipping bucket more clearly in drawing below of the two shaykhs or here (in Hebrew). After seven and a half minutes the tipping bucket would be full of wine and would tilt on its axis and pour twenty dirhams, sixty cubic centimeters of wine which would flow through the pipe to the silver bottle. The top of the goblet is covered; wine would flow directly through the hollow arm to the arm tank. The latter becomes heavy, and the arm would move upward about the axle in the elbow, imitating the motion of drinking. When the tank is full, the siphon ­­­will empty the arm tank, and the hand would descend to its original position.

The automaton of two shaykhs sitting cross-legged on a dais, each holding a bottle and a silver goblet is a duplication of the mechanism just explained. The reservoir is full of water which slowly dripped through an onyx to a tilting pipe. At the bottom of the pipe, a ring was welded, so the pipe is like a “children teeter.” The right side is slightly heavier, and therefore the pipe tilts to the right and water come out on the right. It would take about seven and a half minutes to the tilting bucket to fill (the drawing is just before it overturns) and then water would flow into the pipe inside the column. The rod at the side of the tilting bucket would push the tilting pipe to the left, and the water would flow to the tilting bucket B. After seven and a half minutes it would tilt, and water would flow to other Sheikh’s goblet. This is a drawing of the mechanism with my captions:

Mechanism of the automaton of the two shaykhs


In both illustrations, the faces were erased. This is not accidental damage; there are numerous illustrations in the Topkapi manuscript with damage to the face, without comparison to the number of illustrations which have a different kind of damage. I think this is a case of iconoclasm (from Greek: εἰκών image, κλάστειν break) – the destruction of icons or images for religious or political reasons. Although the contemporary contexts (Taliban, or ISIS) Iconoclasm is an ancient phenomenon starting with Abraham, the father of the Jewish people but also important to Christians and Muslims. In Genesis Rabba (Hebrew: בְּרֵאשִׁית רַבָּה) a religious text from Judaism’s classical period, probably written between 300 and 500 CE it is told:

“So he [Abraham] took a stick and broke all the idols, and put the stick in the hand of the largest.

When his father returned he demanded: What have you done to them?

Abraham said to him: I cannot conceal it from you, a woman came with a plateful of fine meal and requested me to offer it to them, and I did. One [idol] claimed: I must eat first, while another claimed: I must eat first. Thereupon, the largest arose, took the stick and broke them.

His father said: Why are you fooling with me? Have they any knowledge?

Abraham replied: Should your ears hear what your mouth has said?!”

Genesis Raba 38, my translation

I will expand about Iconoclasm and Islam below, but Christianity also had its part. In the 8th century, there were heated arguments, sometimes violent, about iconography. The issue was the interpretation of the second commandment: “thou shalt not make unto thee any graven image.” What appears to some Christians as proper worship, perceived by other Christians as idolatry. These arguments led to the smashing of icons. It is interesting to note that this is an example of government-led iconoclasm with the banning the use of icons by the Byzantine Emperor Leo III in 730 AD.

Those who think Iconoclasm characterizes fanatic religions will be disappointed to learn that enlighten ideologies, at least in the eyes of their believers, supported massive iconoclasm. For example, the French Revolution, the origin of the declaration of the rights of man, is one of the darkest periods of iconoclasm. For three years France was destroying art, It began with the smashing of statues of the Kings of France, and continued in methodical destruction of religious icons, engravings, paintings and burning artifacts from the feudal past. The following quote is from a law from 1792:

“Whereas the sacred principles of liberty and equality will not permit the existence of monuments raised to ostentation, prejudice, and tyranny to continue to offend the eyes of the French people, whereas the bronze in these monuments can be converted to cannons for the defense of the homeland …

All monuments containing traces of feudalism, of whatever nature that remains in churches, or other public places, or even those in private homes, shall, without the slightest delay, be destroyed by the communities. “

The opposition to figural representation in Islam is not based on the Qur’an, but on traditions contained within the Hadith ( الحديث). This is a collection of stories about Muhammad and his words and advice regarding various topics. Within Islam, the authority of Hadith ranks second only to that of the Quran. The two principal objections to figuration are a concern with not taking over the divine creative power and a fear of shirk (شرك), a term that came to mean polytheism and idolatry but originally meant believing in other gods. This duality is similar in my mind to what I learned during my studies at the Mandel School for educational leadership: “thou shalt not make unto thee any graven image.” does not ban on idolatry because it was already said “Thou shalt have no other gods before me” and the ten commandments are “the essence” of faith and contain no repetitions. Hence the second part forbids the use of material representation of God and demand spirituality. Either way, there’s consensus Hadith forbidding all representations that have shadows, whose defacement is obligatory. Some schools of Islamic thought go so far as to see all artists that depict living being (animals and humans) as polytheists.

Over the years, some people who interpret this as permission and possibly an imperative to destroy artworks, in many cases as their initiative. A good example is described by the Ottoman writer Evliya Celebi. In an auction in Eastern Anatolia in 1655 potential bidders were allowed to inspect the goods in their quarters at night, and one of them took the manuscript of Shah-Nama, the Persian Book of Kings, and when he saw it contains miniatures, painting being forbidden according to his belief, he took his Turkish knife and poked their and rubbed the color in their faces with his saliva(?).

The offender was eventually lashed and stoned(?) by the orders of Pasha of Bitlis as a punishment for defacing the manuscript. Clearly, his faith was not accepted by the authorities, or maybe the Pasha was annoyed because of the damage value of the goods.

I couldn’t find any material on iconoclasm in the Topkapi manuscript, and I don’t know if the name of the vandal and the time are known. This  is a partial collection of defacing in the manuscript:

I’d like to close this post with something more optimistic, so I wish the world would be less violent or fanatic, and we will not experience any more iconoclasm because of the Christian, Islamic or Jewish faiths nor by any other ideology.

Automaton of a slave pouring water and the Artuqid court


This is a slave made of jointed copper. In his outstretched right hand, he holds a pitcher decorated with a bird. His left hand is raised and in the palm is a towel, a mirror and a comb(not seen in the picture). This copper slave assists the king in Wuḍū – his ritual ablutions.  This is one of five chapters in the book where the King is mentioned explicitly. I went to learn a bit more about the Artuqids and the Palace in Diyarbakır.

Automaton of a slave pouring water, Topkapi manuscript, 1206.

 How did it work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in siphons, floats, and pulleys can skip those bits. Essentially the mechanism is very similar to the Automatic Pitcher with a few additions, typical of al-Jazari. I modified the original drawing by al-Jazari and added captions to help follow the mechanism:

A modified drawing by al-Jazari with my captions, Topkapi manuscript, 1206.

In the beginning, a human servant removes the copper slave’s hat and pours water with a funnel into the water tank in the slave chest. In the drawing, the tank is half full. At the bottom of the tank, there is a rotary valve (in red). The servant brings the automaton to the King and rotates the hidden valve rod (in grey) near the neck. Water starts to flow through the pipe to the pitcher. There is a partition in the pitcher and the Pitcher spout, designed in the shape of a peacock’s neck, is a Siphon almost touching the partition. When the water rises they will block the airway through the spout, and the air only way out is through the whistle which will make a whistling sound. This is the part that was forgotten in the “Automatic Pitcher.” The siphon, spout, the partition, and even the rotary valve are identical to the “Automatic Pitcher”. The hand holding the pitcher is hardwired and will not move. The hand with the towel consists of an arm and forearm with an axis at the elbow and is free to move. The float is connected through the pulley to the elbow and would sink as the water exit, pulling the arm so that copper slave will offer the towel to the king.

For whom Al-Jazari designed his machines?

In the first chapter, “the Castel Water Clock” al-Jazari wrote :

” This is the basis of the work. Individual parts may be omitted or added according to the place for which it is constructed. For mosques and shrines it may be limited to what is necessary for telling the hours; for the palaces of kings, what may be fitting, such as pictures and other things.”

Naturally, I assumed that all al-Jazari machines were designed for the King and his court, after all, al-Jazari was the court engineer. But when I inspected the book carefully it turns out that the King was mentioned explicitly only in five chapters, including the current “Automaton of a slave pouring water” In only two chapters the  King is mention by his name King Salih, i.e. Salih Nasreddin Mahmud who ruled in Diyarbakir during the years 1200-1222. There are nine more chapters like Category VI chapter one, “the Palace Door” (only in Hebrew) or Category II, chapter four, ” A boat placed on a pool during a drinking party ” (also only in Hebrew) where the King is not mentioned, but from the description and the circumstances the machine was clearly designed for the Royal Court. There are thirty-six chapters which are machines with an unspecified designation. Nobody knows where the Elephant Clock or the Perpetual Flute were located at the time. They could be in the central square, the Palace itself or in some magnificent mosque. I don’t want to pretend that al-Jazari was an engineer in the service of the public. All he did was probably with the Artuqid King blessing. I set out to learn more about Artuqids and their court.

Artuqid kings

Al-Jazari had served three Artuqid kings. Only one of them is mentioned in the book by name: Salih Nasreddin Mahmud who ruled Diyarbakir 1200-1222.

Before him, al-Jazari served his brother Quṭb al-Dīn Sukmān II in the years  1185-1200 years, and he started his service in the Artuqid court for their father  Nūr al-Dīn Muḥammadin in 1181. All three are pretty minor figures in the history of the 12th and 13th centuries. Carole Hillenbrand, Professor Emeritus of History, University of Edinburgh wrote the book: “A Principality in Crusader Times Is: The Early Artuqid State” and several articles, but they contain mainly information about battles and alliances and less about the cultural life. I think if we remember the Artuqid is mainly due to its cultural enterprise. Twenty years or so before al-Jazari the Artuqid court hosted Usama Ibn Munkidh, a Muslim poet, author and knight who wrote كتاب الاعتبار‎ translated a to English as “The Book of Contemplation” which is probably the best-known Muslim source for the Crusader period. Upon the request of the Artuqid king, almost thirty years after the death of al-Jazari, al-Jawbari (الجوبري ) wrote “Book of Selected unveiling of Secrets.”This is a concise encyclopedia of tricks, practices, and devices used by fraudulent Ṣūfīs, false alchemists, jugglers, and quacks. To the best of my knowledge this was not translated to English (unfortunately!). You can add a new architectural language in Artuqid mosques explained in the Thesis of Sharon Talmor Sol(TAU) and Rachel Ward’s paper which present evidence for a workshop for copying manuscripts the Artuqid court. What was the cause of this cultural flourishing?

It is certainly not the size. The title “King” is perhaps a bit excessive. This is the map in the 12th century:

Map of the Principality of the Artuqids in 1200. Wikipedia.

The Artuqid Principality, as you can see, was tiny. Most of Turkey’s territory was controlled by the Byzantine Empire and the Sultanate of Rum. The later is what remained of the Seljuk Empire that controlled, at its prime, a vast area stretching from India to Antioch and from the Arabian Peninsula to Azerbaijan and contained most of the Muslim territories in Asia. However, by the 12th century, the Seljuk Empire was in decline, enabling the existence of small Principalities like the Artuqids. It’s not just the modest territory. Saladin, Sultan of Egypt and Syria, the founder of the Ayyubid dynasty in Cairo took Diyarbakir by storm in 1183 the Artuqids ruled by his grace. It is interesting to note that on the southern wall of the Palace in Diyarbakir appears الله اَلملك واحدي which means Allah is the ruler and drawing of Trebuchet. The Trebuchet is a powerful siege engine which uses a swinging arm to throw a projectile towards besieged city walls. In the second half of the 12th century, the Trebuchet was significantly improved, and those improvements appeared in a military manual written for Saladin. The drawing of the Trebuchet on the walls of Diyarbakir is unique, as far as I know. It can be interpreted as a quality assurance like “this wall would survive a barrage of Trebuchet” or it can be to commemorate the siege by Saladin as “Remember my siege and the horrendous Trebuchet I brought on your heads ” and maybe there is a different explanation altogether?

Picture of the Trebuchet on the southern wall of the fortress in Diyarbakir. Photographed by Lorenz Korn, 2008.

The historical information about the Artuqids doesn’t help me to understand or think about the book. There’s something very optimistic and perhaps even wonderful how this tiny Principality produced such a significant cultural-engineering heritage “It is impossible to overemphasize the importance of Al-Jazari’s work in the history of engineering, it provides a wealth of instructions for design, manufacture, and assembly of machines” Donald Hill in the History Engineering. From the foreword by Donald Hill.

I am adding two pictures of the Palace in Diyarbakir. This is the view from the palace of the  Valley of the Tigris. In Hebrew, the river is called ” Ḥîddeqel” following the ancient Akkadian name ” Idigina”. Most languages in the world follow the old Persian name, Tigrā:

Photo of the Tigris Valley view from the Palace.

Below is the Ulu Beden Tower, a black basalt stone tower in Diyarbakır. It was built in 1208, two years after the death of al-Jazari at age 70.

Ulu Beden Tower, Diyarbakir palace.

The double-headed eagle, the winged beasts and the beautiful Kufic inscription are, in my mind, related to the book. The double-headed eagle also appears on a coin of dirham minted by Mahmoud Nasreddin (the King of Al-Jazari):

A Dirham, 1218, minted in Ḥiṣn Kaifā where the Artukids court was before Diyarbakir.

Some claim that the double-headed Eagle is a Byzantine icon, and one head is facing Rome, and the other one is facing Constantinople. However, the double-headed Eagle symbolizes power and control from the time of Hittites and has countless appearances before and after Byzantium. Are the Tower, the currency, and the view of the Tigris valley helping you see al-Jazary at work? You decide.

The Mechanical Bartender, Cocktails and Rodeo


The official definition of a “cocktail” according to Webster Dictionary is “an iced drink of wine or distilled liquor mixed with flavoring ingredients.” However, we refer to almost any mixed drink as a cocktail. According to Wikipedia, the history of cocktails begins in 1806, but my readers will be surprised to learn that al-Jazari thought about it already in the 12th century. The drink-selector is a man riding a cow. To the best of my knowledge cows are not used in any culture for riding. The nearest exception is bull riding in the Rodeo, and the bulls look like they are not too happy with the idea. This post is a strange combination of all three (al-Jazari, Cocktail, and Rodeo). Let’s Hit the road.

The Wine pitcher, Manuscript from Syria 1315, Calligrapher: Farrukh ibn `Abd al-Latif

How does it work?

The technical explanation as always will be colored in blue, so anyone who is not interested in patents of pouring and extracting wine can skip those bits. Al-Jazari took a large brass pitcher and welded a handsome cow made from cast-bronze. In the center of the cow, there is a valve in the shape of a man riding the cow and his stretched hand points to a circular disk (not seen in the drawing). The pitcher is divided into five containers. In the first tank, there is an aromatic wine, in the second tank, there is a rose-colored wine(Rosé). The third has a yellow wine. I guess he meant what we call today white wine, but I could not find any support for my assumption. In the forth tank there is red wine, and the last one is full of water. The disk has each liquor markup:

Drawing of the disk, Topkapi manuscript, 1206

The rider is a sophisticated valve and when rotated to a point one get his chosen wine, or you can produce different mixes, and al-Jazari proposed a few options. The following drawing helps to understand how did it work. This is a combination of a drawing by the book translator and illustrator Donald Hill with a drawing by al-Jazari, and I added captions:

Integrated drawing of the book translator and annotator Donald Hill with a drawing by al-Jazari.

In the beginning, a servant lifts the cover and pours aromatic wine. The wine enters only the appropriate tank and fills it. The wine doesn’t get anywhere else (except maybe negligible amounts) because the way to the other containers is through the higher pipes. When the tank is full the float in the cage will rise and push the seal upward, blocking the tank. The purpose of the cage is to keep the float in place, allowing only vertical movement. I added the detailed drawing by al-Jazari how to build the cage for the float. Next, the servant would pour the Rosé. The wine will accumulate above the partition until it would pass the height of the pipe and flow into the Rosé tank. Since the pipe opening is lower from the bent in the siphon and the water pipe (please look in the drawing) and the white wine pipe (not in the drawing) No Rosé will flow into any other tank. Only when the Rosé tank is full, the float would seal it in the same way as explained before.  The same logic continues to fill all the remaining tanks. Each of the containers has a pipe which comes out of the cow mouth through the valve. When you turn the selector to one of the six points, the appropriate pipe is connected, and the selected wine comes out.


Cocktail is a drink prepared by mixing alcohol with alcohol or a soft drink. Al-Jazari proposed to mix all four wines, or to mix wine and water, half in half or third wine and two-thirds water. I think it falls under the definition of a cocktail. There is plenty of evidence for mixing alcoholic beverages throughout history but the first time it was mentioned explicitly by the name “cocktail” is in 1806 in the American magazine The Balance and Columbian Repository: “Cocktail is a stimulating liquor, composed of spirits of any kind, sugar, water, and bitters (alcoholic drink flavored with botanical matter).” I found the picture at the Museum of the American Cocktail in New Orleans (it’s not a Museum of my invention, and they even have an educational program?):

The newspaper where the term “cocktail” was first used.

The more interesting question is where this weird name cocktail = Rooster tail originated? One story is that the victor in a cockfight was toasted by his fellows with a special drink crowned with feathers, one for each of them left on the winning rooster’s tail. Another version claims that  Betsy Flanagan, a tavern keeper, served French soldiers a drink in 1779 garnished with tail feathers of her neighbor’s rooster. In other stories, the “Cocktail” has nothing to do with roosters but is a modification of some other word. Two options are: “Cocktail” was derived from the French term for egg cup, coquetel. One  Antoine Amedie Peychaud of New Orleans who mixed his Peychaud bitters into a stomach remedy served in a coquetel. Not all of Peychaud’s customers could pronounce the word, and it became known as a cocktail. The last story is that this was the name of a Mexican Princess named Xochitl. The name means flower in Aztec(?) and some claim it’s the name of an Aztec goddess. Either way, the princess served drinks to American soldiers as part of the celebration of a Peace Treaty signed between Mexico and the United States in the 18th century. “Cocktail” is just a wrong spelling of her name. There are plenty of other stories. The number of colorful stories makes me think they were invented in an evening of too many cocktails and I doubt them all.

It is interesting to note that the myth that drinking a cocktail or even mixing between various drinks (for example drinking beer with a shot of vodka) is the cause of drunkness, or at least a bad headache the next morning is just nonsense. Actual drunkenness and hangover are caused by the amount of alcohol and have nothing to do with mixing or the order of the drinks.


Al-Jazari doesn’t explain why the wine-selector is a man riding a cow? To my knowledge, there is no culture where people rode cows. Oxen were used regularly to pull heavy wagons or for grinding grains in mills and we have the wonderful Minoan art depicting acrobatics on bulls. We think it was a central part of Minoan worship, but to my understanding, we know very little:

The Bull-Leaping Fresco from the palace at Knossos.

The closest thing to riding cows is the Rodeo. It is a popular sport that originated in Spain and Mexico and spread to the United States and elsewhere. During the Rodeo, the rider must stay atop the bull for eight seconds with the use of one hand gripped on a bull rope and the other hand is in the air. I saw it only in the movies, and it’s a pretty sure way to end badly bruised or worse. It certainly doesn’t explain why al-Jazari chose the cow rider as the wine selector?

Cocktails are relatively sophisticated drinks and Rodeo, at least in my mind, is a much more popular sport that goes well with a beer or manly drinks.  To my surprise I  found that  there are quite a few cocktails associated with Rodeo, for example:

Two ounces of Reno Rodeo Legacy Vodka, juice from 1 lemon, 1-ounce triple sec, .5 ounce limoncello, and a splash of simple syrup to sweeten! Add all ingredients into a shaker with ice, shake vigorously, and pour into chilled martini glass. Let’s raise our glasses to al-Jazari, brave bull riders, and tasty cocktails!

Automatic Wuḍūʾ (الوضوء‎) Pitcher and Errors by Engineers


Al-Jazari opens this chapter with the wish of King Salih Nasreddin Mahmud, the third Artuqid king that al-Jazari was serving:

“King Salih disliked a servant or slave-girl pouring water on to his hands for him to perform his ritual ablutions and he wished me to make [something]for pouring water onto his hands for his ritual ablutions.”

The specific reference to ” a servant or slave-girl ” is a bit odd but al-Jazari responded to the challenge and made an “automatic” pitcher.

“Automatic” Pitcher, Topkapi manuscript, 1206.

A servant brings the pitcher and put it on a pedestal; it is a relatively large handsome pitcher. The duck whistles then the water begins to flow from the spout. There are quite a few whistling systems in al-Jazari designs, but this pitcher has no mechanism for the whistling which was probably forgotten. It made me look into error in the book and think about proofreading and editing.

How does it work?

The technical explanation, very minimal this time, will be colored in blue, so anyone who is not interested in siphons can skip those bits. Below is a drawing by the book translator and annotator Donald R. Hill that I edited and attached captions, all remaining errors are my own.

A drawing by the book translator and annotator Donald R. Hill


The pitcher is divided into two horizontally, the bottom part until the partition (orange al-Jazari original drawing) and top from the partition till the pitcher’s neck. The Pitcher spout, designed in the shape of a duck’s neck, is a Siphon almost touching the partition. A Siphon is a tube in an inverted ‘U’ shape, which causes a liquid to flow upward with no pump but powered by the pull of gravity. I wrote quite a bit on siphons, for example here. The atmospheric pressure pushes the liquid up in the tube only if the pipe is full of water. In the beginning, the servant pours water until the float submerges. The water level is too low, below the curve in the duck’s neck and no water will come out of the spout. The cover is also divided into two, and the top is separated from the bottom with a valve and a rotating plug. The servant pours water to the top part of the cover, put the pitcher on the pedestal and rotates the knob. The plug has a pipe through and when rotated will allow water down to the tipping bucket. The latter, when full will tip and release its water so the water level will rise into the neck and the ritual ablution begins. Al-Jazari wrote that the pitcher would whistle to notify the King that the purification is starting, but there is no indication, in the drawing or the text of a whistle. You should be aware that al-Jazari made frequent use of whistles based on compressed air and an intelligent engineer should not have difficulty to implement one here.


Errors and Proofreading

The missing whistle is not the only error in the book. For example, in the Elephant Water Clock al-Jazari writes that the two chains from the float upward connect to a single ring. This is clearly wrong because each chain is connected to another Dragon. There are probably more mistakes. Also, I’m just beginning to study Arabic and cannot detect errors in spelling or grammar.

The issue of errors in the text is on my mind because when I translate my post to English, I always find some errors in the original text. It can be minor typos, it can be real errors. Sometimes I think that mistakes (typing, proofreading, and essence) are like socks, whatever you’re doing, there’s always missing socks in the laundry, and unlike many pieces of advice online the socks are neither behind the washing machine nor inside the bed covers but simply disappeared forever. Despite the proofing, efforts and the goodwill there are always some individual errors that find their way into the text. My love M. read this text and told that the analogy is not working because socks disappear and errors remain. I think that in my head the two are connected because they are an impudent violation of the law of conservation of mass which states that for any closed system, the mass of the system must remain constant over time. Well, socks disappear, and errors appear from thin air.

I know some people are gifted editors or proofreaders, I think it takes a different set of characteristics than the qualities of good engineers. Obviously, a good editor who has deep knowledge of the language and understands the content can see what is clear and what is not and ask questions that help reveal errors. Engineers’ education does not emphasize the choice of words (what you say) nor style (how you say it) and writing quality, in general, is overlooked. Most engineers are more proficient in mathematical clarity rather than writing with clarity. The editor and the proofreader are naturally very skilled readers, and sometimes writers in their own right. There are certainly engineers who read literature although in my experience not that many. Additional attributes, required for an editor or the proofreader, are less obvious to me, and I don’t know how I can learn them. You need a great eye for errors. I read very fast, because of the ability to distinguish between what is important and what is less so. I’m not exactly flipping pages but I “correct” the text as I read and therefore ignore errors. I think patience in reading is required to see the existing version as well as alternative formulations. This is quite the opposite of the education of an engineer which is more directed to purposeful reading and extracting the meaning. Any good text needs a committed editor and meticulous proofreader. I certainly am not both, and I doubt they were available in Diyarbakir. If this is true no one need to wonder about errors the remained in al-Jazari’s book but to remove his hat in awe because they are so few of them.

Pump powered by a water wheel

This post is dedicated to Gedalya and Aba Neeman (grandfather and great-grandfather of my love). On their tombstones engraved “Loved the work and manufacturing of water pumps in the land of Israel.”


This revolutionary water pump is the fifth  pump in Category V which is dedicated to “machines for raising water from pools, and from wells which are not deep, and from running streams.”

Fifth water pump, Topkapi manuscript,1206

Al-Jazari won his fame mainly because of exotic water clocks full of surprises like the Castle water clock or The water clock of the peacocks(in Hebrew) and wonderful automata like The Arbiter for a drinking session and many more. This pump, like the four pumps in previous chapters, shows that al-Jazari was involved in the real hardship of the people around him. Water pumping is essential to any society, for drinking water, watering crops, for excess water and flood pumping, during fire extinguishing and more.

The common pumps in the world of Islam in the 12th century were the Shaduf (Arabic شادوف) and the Saqiya (Arabic ساقية). Both are ancient irrigation tools for raising water. The Shaduf is fully manual and consists of an upright frame on which suspends a long pole with a bucket at one end a counterweight at the other. The operator pulls the rope until the bucket is full of water. With the help of the balancing weight, he lifts the bucket and pours them into the irrigation canal. The Saqiya is a mechanical device raising a chain of buckets or pots using a donkey or an ox to raise the water.

These two pumps are quite similar to a human using a bucket to raise water, only saving work and effort.  The water wheel pump does not imitate the human action and can be seen as an extension and development of the piston pump of Ctesibius (Κτησίβιος), a Greek inventor and mathematician in the golden period of Alexandria, in Ptolemaic Egypt. He wrote the first treatises on experiments with compressed air which earned him the title of “father of pneumatics”. He invented the first piston pump which was apparently very popular in the Roman Empire. At least twenty five such pumps were found in excavations of Roman sites. You can read more here. None of Ctesibius writing survived, we know of him only because of later writers quoting his work. I don’t know about Ctesibius pumps in the Muslim world, and there is no reference to Ctesibius in al-Jazari’s book. We shall never know what, if any, information about Ctesibius was available to al-Jazari.

How does al-Jazari water wheel pump work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in intake or discharge valves can skip those bits. This is a short YouTube clip from “Technology Science in Islam” explaining the operation of the pump:

The energy source of the pump is the water wheel, turning by water flow. The water wheel is connected through gears to a wheel with an eccentric pin (positioned not in the Center) within a rail inside the crank connected to a fixed point. When the wheel turns the rod moves left, and one piston is pulled, and one piston is pushed. This mechanism is called a slider crank mechanism, and it converts straight-line motion to rotary motion, as in a reciprocating piston engine, or to convert rotary motion to straight-line motion, as in a reciprocating piston pump. This mechanism is essential to modern machinery.

Slider crank mechanism

Two pistons are attached to suction pipes going down to the river. The suction pipes continue upward and come together to a single supply. The suction pipe has two directional one-way valves called the intake valve and discharge valve. This is a modified drawing of the piston and the valves. In al-Jazari original drawing there is no water, and both valves are closed, which is possible only during construction and impossible during pumping. In addition, in the facsimile edition, the drawing is cut:

Piston and valves, modified drawing

When the piston moves backward (as in the drawing), the intake valve opens, and the discharge valve is closed. So the pump is disconnected from the supply line and draws water from the river. When the piston moves forward (pushed) the intake valve closes, and the discharge valve opens, and water is pushed upward in the supply pipe. This mechanism is called double action because when one piston is being pushed the second piston is being pulled, so the water supply is continuous.

There are three major innovations in al-Jazari’s pump in comparison to Ctesibius pump. Each one would justify a separate patent today. In the Web, there are lists of what al-Jazari invented, for example, here or here. The discussion on the right for a patent is foreign to al-Jazari and the 12th century in general. In a future post, I hope to write about the history of patents and the concept of intellectual property in The Book of Knowledge of Ingenious Mechanical Devices.

  1. The piston pump of Ctesibius was a manual pump and requires a person to operate it. Al-Jazari used a water wheel to power the pump. Al-Jazari also writes that the water wheel is like the one used to rotate millstones which were well known at his time. This is a big advantage in pumps for drinking water or irrigation
  2. The use of waterwheel demanded to convert circular motion (water wheel) to linear motion (motion of the cylinders). History of the crank (in various forms) is documented from the 2nd century BC in China. Al-Jazari knew the book by the “Banu Musa” which includes a crankshaft. But the crank-slider mechanism is more efficient and remains in use to this day, without significant changes.
  3. Ctesibius’s pump only works when immersed in water. If the water level decreases, it will cease pumping. The al-Jazari’s pump has suction pipes that allow it to function properly above the river water level. A decrease in water level (up to a point) should not affect it at all.

Was this pump built or is it just an idea?

Occasionally someone wonders if al-Jazari indeed built his machines or were they just fantasy blueprints or suggestions that never materialized? Unfortunately we don’t have any proofs. The Palace in Diyarbakir was only partially excavated and there is no archeological evidence of al-Jazari machine. I don’t know any external evidence, for example, a Muslim traveler visiting the Palace in the 13th century who was able to report one of the exotic machines like the elephant clock. However, I’m convinced that the pump, like the Palace door and Castle clock, described in previous posts, were indeed built. I have two arguments:

  1. The number and level of details make you feel that this pump was built. For example,  a rope wrapped on the copper piston to improve sealing. The very use of the rope is a hint of an improvement cycle. It is hard to assume that this was a part of a design which never came to life. Moreover,  al-Jazari is very specific and requested a rope made from cannabis used at his time by sailors. This rope was selected, probably, due to its resistance to water. Could it be that al-Jazari thought about all these details although the pump was not built? Possible but not very likely.
  2. In 1976 the London Science Museum built an accurate model of the water wheel pump. The only difference was that the pump was powered by electricity and not by the Thames. A picture of the model is below. The model produced a steady stream of water with zero problems. It is possible that al-Jazari was a wonderful designer and the museum team was the first to realize his design that just worked great on the first try. It is more likely to think, and experience quite often proved it, that the shift from the drawing board to a real machine requires iterations and improvements. The Museum staff’s success relies thus on the practical experience of al-Jazari’s pump.

    Pump reconstruction. London Science Museum

    Aba Neeman Pumps Ltd.

    In 1980 I learned Chemistry at Tel Aviv University and I was looking for a summer job for my livelihood. I don’t remember exactly how it was arranged, but I went to work in the factory “Aba Neeman Pumps Ltd”, that was owned and managed by the grandfather of my love, Gedalia’s Neeman. In my first day in the factory, I helped cast impellers in the sand. Quite similar to what al-Jazari did 800 years before me. I don’t want you to have the wrong impression about my technical skills at the time. I got 5 minutes explanation about the task and until the end of the workday I broke with hammer unneeded bronze parts. The offices were tiny and no one needed my knowhow in chemistry or computers. Most of the summer I was an apprentice of the lathe operator. It was wonderful. I enjoyed it so much that I took an evening course in Lathe operation. The factory was built by Aba Neeman in 1900. He was a real autodidact; His formal studies amounted to a “Yeshiva”, a Jewish educational institution that focuses on the study of traditional religious texts. All he knew about machines was learned from his work and experimentation. He worked in the metalwork workshop of Leon Stein, who did all the metal work required for the young Jewish community in Israel: repairing wagons, maintenance of pumps, and a repair of the steam boiler in the winery in Zichron. In the absence of electricity and engines, the lathe was operated by the movement of the legs like old Singer sewing machines. Such a manual lathe was the beginning of the factory. Aba Neeman specialized in water pumps and amazingly, the only difference between the pump made by Aba Neeman and al-Jazari’s pump, explained above, is that Aba Neeman’s pump was powered by a diesel engine and al-Jazari’s pump was powered by a water wheel. The Author and farmer Moshe Smilanski wrote that “the pump of Aba Neeman was working for  44 years with no problems” ( from “Inventor and Efforts” by Saul Avitsur [Hebrew]). This was not eight hundred years ago, only in the last century but  “the farmer and author” and a pump that holds 44 years sound so far away, something to long for, like al-Jazari.

The Water Clock of the Boat, a Serpent or a Dragon?


The boat clock is a simpler version of the elephant clock. The scribe indicates the minutes passed and one Dragon (two in the elephant clock) swinging on its axis every half an hour. It looks like an early sketch for the elephant clock or a simpler version for beginners. Perhaps, for this reason, nobody wrote, or at least I haven’t found anything nor restorations or animations in contrast to the abundance for the elephant clock. The Dragon appears here in more detail and also has a drawing of his own but the text refers to it as a serpent just with legs and wings, it got me thinking about the biblical serpent and the story of the tree of the knowledge of good and evil. This post is dedicated to the serpent-dragon, and on this occasion, I also explain the balancing process which allows the dragon to go for a marvelous swing and return safely on his legs.

The Boat Clock, Topkapi manuscript, 1206.

How does the dragon make a flip and Lands on his feet?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in submersible floats or torque and center of mass can skip those bits. In the water clock of the boat, like the elephant clock, the main mechanism is a sinking float, a float with a hole which sinks slowly during half an hour. After half an hour the float is full of water and begins to sink quickly and releases a ball that falls into the dragon’s mouth:

Drawing from the book, Topkapi manuscript, I tilted the dragon to visualize the swing and added the lead weights in his tail and the ball.

The dragon is made of a thin brass plate which was rolled to a pipe and hammered to form the shape of a dragon. The dimensions are not very detailed, but the Dragon’s tail forms a circular ring of four fingers, or 8 cm, diameter. The dragon head is hammered separately and soldered to the ring. The Dragon’s legs are holding an axle which is free to rotate. The ball I added does not appear in the original drawing, but is described in the text and weighs 30 dirhams (درهم), almost 100 grams. When it falls into the Dragon’s mouth, it generates a torque causing the dragon to flip. A torque or moment of force is the rotational equivalent of linear force. The torque is given by the cross product of the position vector (distance vector) and the force vector:

Some of the students I taught physics during the years struggle with cross products and especially with the moment of force. But we all know intuitively that it is easier to open the door by pushing it near the handle than push it near the hinges.(larger r =larger torque). Or when we struggle to remove the lug nuts of a flat wheel, we often use a wrench extension for the same reason – to generate a larger torque.

When the dragon’s head is downwards, the ball falls off, and the lead weight in his tail exert torque in the opposite direction and reset the Dragon position. My love M.  said that the dragon is like a roly-poly and of course she is correct. This is a round-bottomed toy, usually egg-shaped, that tends to right itself when pushed at an angle, and does this in a seeming contradiction to the force of gravity.

Drawing of a roly-poly

The bottom of the toy is made of a high-density material such as metal, and thus the center of mass is low relative to the height of the toy. This is very similar to the lead weights in the tail of the dragon. The ball falls into the Dragon’s mouth function as the finger pushing the toy over. In both cases, the low center of mass exerts a torque that reinstates the upright orientation.

Interestingly enough al-Jazari calls the lead “black lead” (الرصاص اسود) because in his time they called Tin “white lead”. Maybe in a future post, I will write more about the metallurgy of the 12th century.

A Serpent or a Dragon?

Serpentes (snakes) are an elongated, legless, carnivorous suborder of reptiles. They are characterized by the absence of limbs. Al-Jazari serpent has wings and legs making it a legendary creature or a Dragon. Dragons do not exist (sorry if I offended the fans of dragons) and respectively do not have a rigid biological definition. A dragon is a large, serpent-like mythological creature that appears in the folklore of many cultures around the world. Beliefs about dragons vary significantly by region, so horns wings and the number of legs vary a lot. All dragons have superpowers. We are more aware dragons capable of breathing fire in the western cultures but Bakunawa, a dragon from the Philippines, can swallow the moon, and the Vietnamese dragon can control the weather. It can be argued that the Dragon figure was influenced by various snakes, especially spitting cobras, bats (wings) and giant lizards and in the modern era extinct dinosaurs. In the Wikipedia entry of the “Elephant clock” appears this wonderful quote in the name of al-Jazari signifying his “multicultural mentality”:

  “The elephant represents the Indian and African cultures, the two dragons represent Chinese culture, the phoenix represents Persian culture, the water work represents Greek culture, and the turban represents Islamic culture.”

Al-Jazari didn’t write these lines. Such errors are amazing and funny and are one of the risks of a free-content encyclopedia relying on volunteers editors.

In contrast to the threatening figure of the Western Dragon, Chinese Dragon is a symbol of strength, integrity, and wisdom. The Chinese Dragon is depicted as a lizard-like creature without wings and four clawed feet and long tendril appended to each side of the snout. Al-Jazari’s Dragon is not very Chinese. However, at home, we have a facsimile edition of the Sarajevo Haggadah.” It’s Passover Haggadah written in Barcelona around 1350, and it is considered to be the oldest surviving Haggadah. The Haggadah is displayed at the National Museum of Bosnia and Herzegovina in Sarajevo, and this is the origin of its name. To my surprise, the Haggadah is packed with dragons. On top of this, in the 19th century in Paris, a small book was printed: – L’ornementation des Moyen-âge. This is a collection of illustration from medieval manuscripts and also includes many dragons. The dragons in all three books are very similar, the same general, lizard-like structure, the same animal head which is not completely defined, small wings and legs. If my rationality hadn’t so constrained me, I would be convinced that the three illustrators visited some mysterious zoo and made a drawing of the dragon that was held not far from the reptile room.

Right side dragons from Haggadah Sarajevo, in the center the Dragon of the Boat, Topkapi manuscript and to the left a dragon from L’ornementation des manuscrits au Moyen-âge

All this discussion about snakes with legs took me back to the Bible story, Genesis 2-3.  Adam and Eve were in the garden of Eden, where “And out of the ground made the Lord God to grow every tree that is pleasant to the sight, and good for food; the tree of life also in the midst of the garden, and the tree of knowledge of good and evil.” God allowed Adam and Eve to enjoy the fruits of the Garden except for the tree of knowledge, “for in the day that thou eatest thereof thou shalt surely die. Now the serpent was more subtil than any beast of the field which the Lord God had made” The Serpent Tempted Eve claiming “then your eyes shall be opened, and ye shall be as gods, knowing good and evil.” Therefore the snake lost its legs and got in trouble with men kind: “And the Lord God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life:

Genesis 2-3 King James Version

But did al-Jazari know the Biblical story about how the ancient serpent lost his feet?

Years ago I visited the Topkapi Museum in Istanbul, and near one of the swords there was a summary of the “The Binding הָעֲקֵידָה Ha-Aqedah” only, Ishmael (and not Isac) is the victim and the hero of the story. First, I thought there was a confusion, but this is of course just my ignorance. Eid al-Adha ( عيد الأضحى‎) ‘Feast of the Sacrifice’ is the second of two Islamic holidays celebrated worldwide each year. The sacrifice celebrated is the sacrifice Ibrahim (Abraham) our father, was asked by God to sacrifice his son Ismail (Ishmael) though the Qur’an does not name the son. In my eyes, both stories are equally heinous, and already as a child, I remember my inner resistance. Like the story of the Binding, the story of the garden of Eden in the Quran is completely different:

“And you, Adam, inhabit the Garden, you and your wife, and eat whatever you wish; but do not approach this tree, lest you become sinners.

But Satan whispered to them, to reveal to them their nakedness, which was invisible to them. He said, “Your Lord has only forbidden you this tree, lest you become angels, or become immortals.”

Quran, Surah 7 elevation, Translated by Talal Itani.

In the Quran, there is no tree of knowledge. The only tree mentioned by name is the Tree of Immortality ( شجرة الخلود Shajarat al-Kholoud ) The Serpent is not the seducer but the devil himself, and he is tempting Adam and Eve with eternal life. In Surah 2, The Heifer, appears Iblis (إبليس), which is another name for the devil in Islam. Eve, as a woman, is the main guilty in the original sin, both in Judaism and Christianity. In Islam Eve is Adams’ partner and clean from sin.  It is very unlikely that al-Jazari didn’t know the Serpent from the story of the creation and knew only the Quran version and the source of the legs and wings who can tell?


Al-Jazari Combination Lock and the Boxes from Isfahan

“This Ifrit bore me off on my bride night, and put me into a casket and set the casket in a coffer, and to the coffer he affixed seven strong padlocks of steel and deposited me on the deep bottom of the sea that raves…and this wretched Jinni wotteth not [does not know] that destiny may not be averted nor hindered. ”

The Story of King Shahryar and His Brother from The Arabian Nights, translator Sir Richard Burton,1850.


In Category six that consists of “dissimilar designs” al-Jazari describes “A lock for locking a chest using 12 letters of the alphabet”.

Locking board in the alphabet lock, Topkapi manuscript, 1206

Description of the Chest by al-Jazari

The technical explanation, as always, will be colored in blue, so anyone who is not interested in cylinders or cotter-tapered pins can skip those bits. This is a chest with four combination locks in the four corners of the cover. Each combination lock uses sixteen out of twenty-eight letters in the Arabic alphabet; it uses the letters without a diacritical mark, a point, or sign added to a letter to distinguish it from another similar letter. For example, the difference between bāʾ ب (comparable to b in English) and nun ن (comparable to n in English) is the location of the point below or above the letters. Al-Jazari doesn’t explain his choice, perhaps to prevent mistakes.

The four dials

Chest reconstruction from HTTP://WWW.JAZARIMACHINES.COM/EN (link is not working anymore)


The four dials on the chest cover are relatively complex. Each dial consists of three disks with a triangular notch in its outer perimeter. When all the notches were aligned, the chest could be opened. I attached the original drawing of al-Jazari cross-section of the dial with the modern drawing of Hill and added captions:

Integrated drawing of the lock components, the original drawing by al-Jazari, with the modern drawing by the book translator and annotator, Dr. Donald Hill

Since it still seems complicated to comprehend, I added the drawing of the components before assembly:

The dial component, a drawing by the book translator Donald Hill, with my captions

When you turn each of the three cylinders to their proper letter, all notches are aligned and allow the opening of the lock. It requires the knowledge of twelve letters, three letters per each dial multiplied by four dials. This system is held in place together but allows convenient rotation of its components using a cotter-pin. When you want to change the code, you remove the pin and mechanically rotate the disc so the location of the notch will match the chosen letter.

The Isfahan Boxes

None of the wonderful machines of al-Jazari survived the hundreds of years passed, and all we have are beautiful manuscripts. I fantasize about an extensive archaeological excavation in the Palace in Diyarbakir that would reveal remnants of the castle’s clock or any other monumental work. Until then, both boxes with alphabet locks from Isfahan in Iran dated to the late twelfth century are the closest thing to time travel, to see al-Jazari at his work. In the David Museum in Copenhagen, there is a fragmented brass box inlaid with silver and copper with four alphabet locks. The four dials are in a straight line and not in the four corners of a rectangle, but the similarity to al-Jazari’s chest is evident. Like al-Jazari each dial contains 16 letters. The letters which are used are without a diacritical mark. There is a resemblance to the locking process and the details of the mechanism. The box is simpler, and each dial has just two cylinders. Only eight letters (and not twelve) are required to open the crate. On the box there is the maker signature saying:

“Work of Mohammed b. [Ben] Hamid al Asturlabi

 Al Isfhani in the year

Five hundred and ninety-seven [1200 AD]

And I have tested it[it works]”

Fragments of a box made by Asturlabi, 1200 AD, Museum David Copenhagen

To my astonishment there in another safe from the same period by Asturlabi at the Boston art museum. This box also has four alphabet locks of two cylinders, creating eight-letter code. This time also there is an additional three guards’ façade, probably as symbolic protection from a later period. The signature indicates that the box was prepared by Asturlabi four years earlier (593 to AH or 1197 AD). Although it’s childish, I can’t help feeling a bit left out: why two boxes by Asturlabi from Isfahan have survived and not even one machine by al-Jazari? There is no answer, nor there can be one.

Box by Asturlabi,1197 AD, Isfahan, Boston Arts Museum


From the name of the maker, it is obvious that his profession and probably the family profession was producing astrolabes. Astrolabe (ٱلأَسْطُرلاب) is a sophisticated device of astronomers and navigators to measure the angle of a star above the horizon. It has many functions but was used primarily for finding latitude when you know the local time or as a clock when you know your position. There is a good explanation and a demo here. Four astrolabes from the 12th century created by Asturlabi family from Isfahan still exist, but I could not find their pictures. There are pictures of astrolabes from Isfahan from the 9th century until the 16th century, and this is one beautiful example:

The 13th-century astrolabe from Isfahan, Muhammad B.AbiBaker, The Museum of the history of science, Oxford.

Surprisingly, perhaps, there is a link between the astrolabe and the combination locks. The lock consists of rotating cylinders with respect to the alphabet circle. In the astrolabe, there is a framework called “Rete” bearing a projection of the ecliptic plane and several pointers indicating the positions of the brightest stars. This frame is free to rotate in respect to the astrolabe disk, called the mater (mother). Both the astrolabe and the alphabet lock are rotating mechanical systems around the center. This is done in both cases by using a cotter pin (a tapered pin) that holds all the components in place and allows rotation around an axis. This pin has the shape of a horse head, hence his name in Arabic فرس (mare). I attach a photo of astrolabe dismantled; you can see exactly the same mechanism and the same cotter pin (red circle) as in the drawing by al-Jazari above.

Astrolabe dismantled for parts. The cotter pin in the red circle

If you really want to go on a historic-scientific journey, you can read the guide that Geoffrey Chaucer wrote for his 10-year-old son Lewis. Chaucer, one of the fathers of the English literature and the author of “The Canterbury Tales” was also an astronomer. This is the first publication in English on this topic as well as a great introduction to the Astronomy in the 14th century. The guide contains more than fourty (!) uses the astrolabe.

Who’s ahead?

Al-Jazari wrote  in the opening paragraph:

“The earlier [workers] in this craft made locks for locking and opening by means of the letters. Among them were [those that] locked by means of  four  a chest and made a lock on its lid as I shall describe”

Al-Jazari, obviously, did not claim primacy. Is it possible that the Isfahan boxes are part of the boxes that al-Jasari mentioned? Could it be that al-Jazari book got to Isfahan and inspired Asturlabi to build his boxes? The answer is probably no to both. The boxes were made in the years 1197-1200. We don’t have an exact date for completion of the book.  Rachel Ward claims that the book was written between 1200 to 1197. It’s a little earlier than Donald Hill who believed that the book was written between 1204-1206. The small gap is due to different sources. Hill was relying mainly on the copy from Oxford University, and Ward is basing her calculation on the earlier copy of Topkapi. Either way, the closeness between the time the book was written and the dates of the production of the boxes in Isfahan almost negates the possibility of mutual influence. Much more likely is both the Isfahan boxes and al-Jazari’s chest are part of the same rich material culture in the Muslim world at the time.

It is interesting to note that the first alphabet lock in Europe is probably the work of Giovanni Fontana, A Venetian engineer from the 15th century, three hundred years after al-Jazari. Fontana was very diverse, including measuring heights with falling stones, water and sand clocks, and trigonometric measurements. He wrote one of the first technology books in the Renaissance: “Bellicorum Instrumentorum Liber.” The book includes siege machines but also fantastic inventions like a bird propelled by a rocket, and an early version of four wheels bicycles and last but not least an alphabet lock:

The alphabet lock of Giovanni Fontana, 1420-1430