The Arbiter for a drinking session


This is a drinking game for the effervescent parties in Diyarbakır Palace as we met in The automaton who drinks the king’s leaving and A boat placed on a pool during a drinking party (in Hebrew).

The Arbiter is a complicated automaton (a self-operating machine) which includes: A slave (جارِية) pouring wine to a goblet in the lower level. Above her, on a balcony, there are four slave girls who play music on a flute, tambourine and a lute. Above them, there is a half-naked male dancer in a niche, and on top of the dome, there is a horse rider carrying a lance. During the party, the musicians play their instruments, the dancer dances (I swear!) and the horse and the rider rotate slowly. When commotion stops the slave girl tilt the bottle and pours wine to the goblet. A servant (a living person) takes the goblet and serve it to the participant the spear points to his direction. The process repeats itself twenty times, almost seven hours in total. At that time the black doors behind the dancer open and a man emerges out of the door, his hands are in the air, signaling that celebration is over and there is no more wine. Al-Jazari calms the worried reader, saying that the head of the assembly can choose to refill the reservoir. The wild parties in Diyarbakir can raise a lot of questions about the crazy amounts of wine, the half-naked dancer, and more. Maybe I will write about all this in the future. I want to focus on clothes, did observer of the automaton in the 12th century knew she was a slave by her dress?  What can we learn from the text and the illustrations about clothing in the Artuqid palace?

The Arbiter for a drinking session. Topkapi manuscript, 1206.

How does it work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in floats, Tipping buckets or camshaft can skip those bits. The illustration below is my modification of the drawing from the book; it will help us to follow the mechanism:

Drawing of the mechanism

In the beginning, a servant lifts the dome (1) and fill the reservoir (2) with filtered wine.  At the bottom of the reservoir, there is a thin pipe, so wine is dripping to the tipping bucket(3). I wrote about tipping buckets before, for example in the fountain of the two tipping buckets (in Hebrew). In the front view, you can see the tipping bucket in action. After twenty minutes the bucket is full of wine, and it becomes overbalanced, and tips down, emptying itself on the scoop wheel (4) which turns the adjacent teeth wheel (5) which turns the 900 teeth wheel(6) which is connected to the rider axle(more clearly seen from the side). This makes the rider rotates, and the “lucky” participant that the spear is pointing in his direction will get to drink the goblet. I used quotation for “lucky” because the goblet contains a liter of wine, more than an entire bottle! I don’t know what the alcohol content in the 12th century was, but it seems like a sure way to get drunk with a severe hangover. I do not want to think about someone who was lucky enough to win two goblets during the seven hours of the party.  The wine from the scoop wheel is collected and falls on the second scoop wheel(7). The rotating wheel rotates the axle and the pegs(8)connected to it, hitting the levers connected to the musician’s arms. This causes the up and down movement, simulating the drummer bit and the playing of the lute. The rods, an early version of camshaft transform the circular motion into linear motion were the rods pattern creates different drumming bit and lute music. The wine flow from the 2nd scoop wheel to the air tank, pushing air in a narrow pipe with a whistle at the end(9). This produces the sound of the flute player. Finally, the wine goes down in a hidden tube (10) through the slave body and fills the bottle. The latter is on an axle, and the weight will cause it to tilt and fill the goblet. For clarity, I skipped two mechanisms. Readers who love to ponder on this kind of gadgets can try to decipher the remaining components and questions will be, as always, appreciated.

Fashion and clothing in the “Book of Knowledge of Ingenious Mechanical Devices.”

The choices of clothing by Muslims reflect their religious and cultural world. We call the veil worn by some Muslim women to cover their hair- hijab (Arabic: حجاب). In the Qur’an and other classical Arabic texts, the term was used to denote a partition, a curtain and it is a generic term for modest attire. During the Hajj (حَجّ), the pilgrimage to Mecca, one of the five pillars of Islam, the men wear a white outfit that was not touched by a needle or thread (how is that even possible?).  What (if anything) can we learn about life in the 12th century in Diyarbakır by looking at the illustration and the few direct references of al-Jazari to clothing details?

Five slaves from the “Book of Knowledge of Ingenious Mechanical Devices” Topkapi manuscript,1206

In the top left illustration, we can see a young black slave (غلام) truncates the candle wick from The candle clock of the swordsman (Hebrew). No explicit description of him in the book but his attire is the simplest, in comparison to all the other slaves and includes a short red dress with stripes on the sleeves. The sleeves’ stripes appear in almost every dress of slaves or free men. I don’t know if this was the fashion in Diyarbakır or the stripes had a meaning or use? If a knowledgeable reader can enlight me, I would love to learn.

The slave girl pouring wine at the center is from the automaton in the present post. She wears a blue dress or gown with decorations that cover her from neck to ankles. She also has two brown stripes on her sleeves. The garment doesn’t look “cheap” or “service uniform” Her black hair can be seen under the cover. Although her dress could have been worn by devout Muslim today her head cover is not acceptable by contemporary moderate standards (hijab) and certainly not by more religious Muslims demanding a niqāb or chador.

We met the slave washing the king’s hands here (in Hebrew). The illustration, in this case, is large and rich with details. The blue dress is very similar, if not identical, to dress of the slave girl. It is particularly interesting. Muslim men are forbidden(حَرَام‎ ḥarām) to wear silk clothes or gold jewelry. This is not from the Quran but a later story told by Ali Ibn Abi Talib, Muhammad cousin and the fourth Caliph accepted by both Sunni and Shia. The restriction is very specific but interpreted as an echo of the biblical verse:

“The woman shall not wear that which pertaineth unto a man, neither shall a man put on a woman’s garment: for all that do so are an abomination unto the Lord thy God.”

(Deuteronomy 22:5 King James Version)

It is possible that his red jacket without sleeves is enough to distinguish between them? He is also wearing a small red hat quite similar to the fez (more correctly ṭarbūsh). It is interesting to note because the ṭarbūsh is usually attributed to the period of Sultan Mahmud II (1808-1839) when it was introduced as part of the Ottoman Empire judges and spread to clerical circles and the educated elite.

The next slave, to the left and below, is from the automaton of a standing slave holding a Fish and A Goblet. In this case, al-Jazari himself provides a relatively detailed description of the dress:

” He is a standing slave, ten years old in appearance, dressed in a short jacket (farajiya) with a robe(qaba) underneath it, and a cap (qalansuwa) on his head.”

The qaba (قابا, I hope I spelled right?) is a type of a robe with sleeves, at mid-calf –between the knee and ankle that has a diagonal fastening of one side over the other. The “Encyclopedia of Islamic Civilization” claimes that in Abbasid times qaba belonged to the military? According to the illustrations in the book, the qaba was widely used among slaves and free men. The hat (qalansuwa  = قلنسوة‎) is written like the Arabic city in the center of Israel; I don’t know if this is the origin of the city name. This hat was quite popular, and Harun al-Rashid was wearing this hat in his nocturnal wanderings through Baghdad in disguise. Unlike the qaba which repeats itself in many illustrations, there is quite a selection of headdress. For example, the slave girl who emerges from a cupboard holding a glass of wine is covered with a colorful scarf with a picturesque ribbon. Quite similar to today hijab. She is also wearing loose red trousers under the qaba. This combination can be found both in the book and outside.

Eight “free” people (in the sense of not slaves) from the “Book of Knowledge of Ingenious Mechanical Devices” Topkapi manuscript,1206.

The top left illustration is the scribe from the elephant water clock. There are three scribes in the book, all three wear green qabas with brown stripes on the sleeves and wear pale blue turbans. I couldn’t find any evidence of “professional clothing” of scribes. You should also note that the scribe has a beard. Allowing the beard to grow (لحية) and trimming the mustache is mandatory in Sunni Islam and is considered to be Fitrah (فطرة‎) or the state of purity and innocence we are all born with including the natural tendency to distinguish between good and evil and to believe in the existence of Allah. As none of the slaves are bearded, they probably weren’t Muslims.

The two Sheikhs are part of the automaton in Category II dedicated to vessels and figures suitable for drink sessions.  Al-Jazari did not write anything about the Sheikhs, but Sheikh (( شيخ is a title given to the leader of the Bedouin or Arab tribes. The meaning of the name in Arabic is old, although the Sheikh is not necessarily old. They are also dressed in qaba and turbans. I don’t see in the illustration a difference between the of Sheik’s qaba and the slaves’  qaba. It is quite possible that there were large differences in the quality of the cloth or decoration which are not captured in the illustrations. However, the turban characterizes only the free people. Before anything else, the turban was practical in protecting the eyes from the sand and providing the face protection from the sun.  On top of this, the turban (عمامة, pronounced amama) was part of Muslim’s traditional attire and their identity. The turbans were a source of pride and a symbol of religious affiliation. Taking a man’s turban was considered a humiliating act, touching someone’s turban was perceived as an insult. It explains well why none of the slaves wear a turban.

The last picture below is from the musical boat(Hebrew). This is the King and his boon companion ( نديم =Nadim) I wrote about it here (Hebrew). Everyone is wearing a qaba, including the King himself. His blood-red qaba has gold trim. On top of the decorations, everybody has, he has additional decorations of the collar, the cufflinks and the fringes of the qaba as well as a golden belt. Red is not necessarily Royal, another member of the party is wearing red, though with fewer decorations.

I’m pretty sure al-Jazari was very surprised from this post, and it didn’t occur to him that the illustrations he prepared to improve the understanding of his machines, and are truly groundbreaking, would become a fashion guide for 12th century Diyarbakir. However eight hundred and twelve years later this is the only window that would allow me to peep into the  Palace in Diyarbakır. At least for me, this was an interesting journey.

The Elephant Clock – Multiculturalism or a Circus?


The elephant clock is by far the most popular of all al-Jazari’s works. There are few modern reconstructions of it, some in different exhibitions and museums, but also in the Dubai Mall. It has a variety of animations in 2D and 3D, and it has a Wikipedia entry of its own. Due to the complexity of the mechanism, I divided this post to two; in the first part, I will explain what the viewer sees and try to explore the sources of the magic. The second part will be more engineering oriented, and I will explain how the mechanisms work in the backstage, and what is so unique in this clock.

The Elephant clock, manuscript from 1315, Syria

What does The viewer see?

An elephant,  approximately one meter and twenty centimeters long, carries on its back a canopy with four pillars and a castle. On top of the castle’s dome, there is a bird. Inside the elephant, there is a hidden water reservoir and a sinking float(a float with a hole which sinks slowly) during half an hour. More details in the next post. In the canopy sits a scribe holding a pen pointing at semi-circle with tick marks. During this half an hour the scribe rotates and his pen indicating the minutes passed. At the end of the every half an hour, the scribe will return to its original position. At the same time, there will be quite an impressive show. Between the elephant shoulders, ride a mahout (the elephant keeper and driver). In his right hand, there is an ax and a mallet in his left. Every half an hour the mahout will strike the copper elephant, first, with the ax and then with the mallet. In the castle balcony sits a man, his hands are on the heads of two falcons like he keeps them from opening their beaks. Once every half an hour, he would raise his hand, right or left and the Falcon will emit a ball. The ball falls to the Dragon’s maw, make the dragon swing on its axis and lay the ball on the cymbal in a jar. Also, the bird on the dome will go spinning. Above the head of the Falconer (falcon trainer), there is a semi-circle with fifteen black holes. Every full hour one hole will be colored white, thus indicating the passing hours since sunrise.

You can see a short video demonstrating the elephant clock and explaining the mechanism. A fuller explanation in the next post.

Why an elephant?

In Wikipedia, the Elephant water clock entry, it says:

“The elephant represents the Indian and African cultures, the two dragons represents ancient Chinese culture, the phoenix represents Persian culture, the water work represents ancient Greek culture, and the turban represents Islamic culture” signifying the multicultural mentality of the intellectual al-Jazari. “

The quote is attributed to al-Jazari himself. I am afraid that the whole concept of multiculturalism is completely foreign to the 12th century and al-Jazari. The quote certainly is not by al-Jazari, but whoever wrote it (who?) explained the wealth of the clock. It made me think, and first of all about the elephant.

The Middle Ages and strange elephants

The trade routes in the middle ages were spread over Europe and the Middle East but also in India, China, and  Africa. On the East coast of Africa, they traded ivory, gold,  ebony, and slaves. China exported silk and porcelain and India spices and drugs. It means that rumors about elephants, giraffe, and other exotic animals reached Europe but the artists that drew the manuscripts had never seen an actual elephant drew them based on his imagination. There is an entire site dedicated to the weird drawings of elephants. I give just two examples:

Thomas of Cantimpré, Liber de natura rerum, France 1290

A hoofed wooly elephant “Livre des simples médecines” a manuscript from the 15 century.

The original manuscript was unfortunately lost, but the manuscript from Topkapi is from 1206, I wrote about it here. This is the year al-Jazari died, so it is probably “firsthand”  copy. You can see that the elephant looks like an Asian elephant and the mahout and the canopy are located right. The acquaintance of al-Jazari with elephants is not necessarily surprising, although I couldn’t find any evidence for elephants in Diyarbakir. Arab rulers held menageries or collection of exotic animals. In addition to the curiosity and pleasure they provided, they demonstrated the wealth and the power of the ruler and demonstrated the impact of the sovereign from India to Africa. Offerings of rare animals were part of the diplomatic process and sometimes part of the tax system. Until the 13th century, the agreement between the Nubian Kingdom and the Muslim rulers of Egypt demanded from Nubian people to provide Egypt with three hundred and sixty slaves annually and wildlife. It This was the primary source for giraffes in the Sultan of Cairo menagerie.

Book of the animals, Syria, 15th Century.

The use of animals as a diplomatic gesture is well documented. For example, Baybars, the Mameluke Sultan of Egypt and Syria in the 13th century gave elephants, giraffes, and zebras to the King of Spain, Emperor of Byzantium and the Mongol Khan. In the 10th century, Cordoba sent a giraffe to Tunisia and a story I particularly like about the elephant, Abul-Abbas. Harun al-Rashid,  the Abbasid caliph in Baghdad, sent an Asian elephant to Aachen, Germany to the Carolingian emperor Charlemagne. It happened in the 9th century, and surprisingly enough, there’s a Jewish angle to this story. The elephant was brought by Yitzhak the Jew. There is a historical novel “The travels of Isaac the Jew and Abu Alabas the elephant”(in Hebrew). It is interesting to note that other presents including an elaborate water clock made of brass, described in the Royal Frankish Annals were sent with the elephant. The water clock marked the 12 hours with balls of brass falling on a plate every hour, and also had twelve horsemen who appeared in turn at each hour.  Perhaps al-Jazari knew the story as part of his extensive knowledge of water clocks?

The Elephant Clock and the Circus

The diplomatic delegations and the royal gifts indicate that the Elephant was a symbol of power and wisdom, but in the context of the elephant clock, I think more about the circus and exotic acts. The elephant is made of copper and is just a stage for the show, but the swinging dragons, the Mahout with his fearsome tools, the Falcons and the spinning bird form a great circus number. An exciting circus act has, in my opinion, four components, not in binding order, not always all of them, and certainly not of the same weight:

  • Freshness (something new)
  • High skills
  • Sense of danger
  • Magical picture

I looked at several iconic circus shows such as Jules Léotard, a French acrobatic performer that made history as the first man ever with the aerial act on a trapeze. It must certainly meet the requirement for ” Freshness or something new.” The elephant clock is also the first of its kind, no clock ever, before or after is similar, and everyone who watches it, even today, is amazed. Secondly, high skills – Léotard practiced its aerobatic stunts over his parents’ pool before he revealed them in 1859  in Cirque Napoleon in Paris. Then he appeared in London before an audience that went crazy because of his aerial act and flips between five trapezes with only a pile of mattresses to protect him. The elephant clock also demonstrates high proficiency and skills both to the innocent and skilled observer: The control of the timing using the sinking float, the complex movement of the three characters(the mahout, the scribe and the man in the balcony), the virtuoso swing of the dragons. All are innovative engineering tricks demonstrating al-Jazari skills in water clocks and automatons. The crowd in the circus was afraid for Léotard life, and the sense of danger, which automatons be definition lack, intensified the experience.

Jules Léotard, a French acrobat, 19 century

Last but not least, the image. Léotard, like all circus performers, could be dressed in a sports suit. But as you can see in the picture he’s wearing theatrical shorts, bracelets emphasize his wrists, and the collar of his shirt reminds us of a royal necklace. All this help to imprint his image in our mind.  The picture that al-Jazari created is a lot more than the sum of its components and is intriguing audiences till this very day.

The Castle Clock


Al-Jazari opened  “The Book Of Knowledge Of  Ingenious Mechanical Devices”  with a monumental clock, perhaps the most complex of all ten water clocks and candle clocks explained in the book: The Castle Clock.

Sometimes you know you read a wonderful book the second  you read the first paragraph:

“Call me Ishmael. Some years ago – never mind how long precisely – having little or no money in my purse, and nothing particular to interest me on shore, I thought I would sail about a little and see the watery part of the world. It is a way I have of driving off the spleen and regulating the circulation.”

Moby Dick by Herman Melville

In the right hands, the beginning of a novel can make you feel like you were abducted from reality and you are drifting down a river which will take you to other worlds. Not only engineers who open al-Jazari’s book are captured immediately by its magic of the machines he designed eight hundred years ago. We will never know if al-Jazari wanted a powerful opening to demonstrate his ability at its best, or he positioned machines at random order and was surprised by the very question? This post hopes to explain the Castel Clock as well as discuss what we can about al-Jazari from the text.

How does it work?

The Castle Clock had a complicated movement throughout the day, and it is on the boundary between a clock and an automaton(a machine that performs a function according to a predetermined set of instructions). There is something theatrical in many automata. Sometimes it is by design, like the automata in Greek theater used for “Deus ex machina”, literally “god from the machine”. Sometimes there are other objectives like the lion automaton built by Leonardo da Vinci for François Ier, king of France. When the King tapped the lion with his sword, its body opened and presented lilies, a symbol associated with the French royalty. The clock by al-Jazari is also very theatrical.

The Castle Clock from a dispersed copy, 1315.

At the beginning of the day all twenty-four doors, in two rows, are closed and the Golden Crescent,  which is a little hard to see in the picture, is positioned to the left. During the day, the half-moon is moving right, and  every hour three things are happening:

  • The upper doors open and a figure comes out and stands as if he had suddenly emerged.
  • The lower door is rotating on its axis, and the text “Allah al-Malik” meaning ” God is The King and Owner of “
  • The Two falcons with outspread wings lean forward and cast a bronze ball into a vase, inside the vase a cymbal is hung, making a sound which can be heard from afar.

The picture of the falcon is taken from a dream or myth. Horus is one of the most significant ancient Egyptian deities. He was most often depicted as a falcon. Horus had many battles with Seth, the god of the desert, in which he lost his left eye, then a new eye was created for him called “the eye of the Moon” or “the diamond” and symbolizes an endless vision. I have no reason to assume that al-Jazari was familiar with Egyptian mythology, but who knows?

Above the upper row of doors, we can see the Zodiac sphere. At the beginning of the day, the sun will be on the eastern horizon, about to rise. The sun climbs until noon, then descends until nightfall and the six signs that have been visible will disappear, and the six that have been hidden will appear. At noon the drummers drum, the trumpeters blow, and the cymbalist plays his cymbals for a while.

Al-Jazari does not write anything about the reason for multiple mechanisms to display the time. The crescent actually functions as a modern analog clock hand, and the rest are just “decoration” and maybe a resonance box. In the world of modern engineering, it could be considered excessive and even wasteful, but there is magic that passes through centuries of the Falcons even if there is no additional information.

Erich Kästner, the wonderful author of Pünktchen und Anton(Dot and Anton in English), was concerned:   ” By the children who would prefer to eat porridge for three days than deal with such complex issues as his reflections [my translation from Hebrew]. He came up with a different font “so if you see something like that you can skip it altogether…” It seems to me this even more needed for technical explanations of engineers that will be in blue.

The Castle Clock is a sophisticated version of the classical water clock or clepsydra where time is measured by the regulated flow of out a vessel where the amount is then measured.  The difficulty is that the water flow rate is not uniform and depends on pressure (altitude) of the water in the vessel. To overcome this problem, al-Jazari used a conical plug and the float chamber.

Conical plug, the Castle clock, Topkapi, 1206

The main reservoir is feeding the float chamber through a conical plug thus whenever the water level drops the valve (a float that is a plug in a cone shape) goes down with the water level allowing the chamber to be refilled. Every time the chamber is full of water, the conical plug will seal the chamber isolating it from the main reservoir. In this way, the float chamber is always full of water and therefore the water flow at a constant rate and does not depend on the height of the water in the main reservoir.

A drawing of the clock mechanism, Topkapı manuscript, 1206, my captions


At Sunrise a servant makes sure that all doors are closed and the time cart is on the right side (looking from the back). During the day water will flow at a rate determined by the flow regulator and the main float would drop with the water level at the main reservoir. The main float is made of copper, and it is quite heavy.  When it drops, it pulls the rope, which through the pulley would turn the main disk and pull the time cart attached to the golden crescent which would move to the left at a constant velocity indicating the time passed from sunrise. Every hour the cart will progress one door, and a smart mechanism would open the doors while dropping down two bronze balls. The balls would roll down and reach an opening above the heads of the Falcons. The curving claws of the Falcons are welded to a copper tube that can rotate on its axis. The falcon stands upright because of a balancing weight. When the bronze ball drops down, it changes the balance, and the falcon would lean forward, and the falcon wings, attached to a body on a hinge will spread open, and the ball will fall on the cymbal hidden in the vase. Now that the falcon head is light again, the balancing weight will bring him to its original position. The clock is packed with similar invention and  “patents”.

A drawing of the falcon mechanism, Topkapi manuscript, 1206

The book contains almost 50 pages explaining the various mechanisms with detailed construction instructions. Readers who are interested in the details can learn them here and see the simulation here


What did I learn about Al-Jazari?

We have no information about al-Jazari except what is in the text itself. We can “pick” the book to learn about al-Jazari and his world. Consider the adjustable flow regulator intended to ensure that the clock movement fits the changing length of the day. This controller is a small engineering marvel itself, but I am interested in it because of the triple encounter it offers with al-Jazari and his world:

  • First, al-Jazari is a man who is familiar with the literature of his time. The opening lines of the Castle clock chapter are: “I followed the method of the excellent Archimedes in distributing the twelve signs of the Zodiac. Al-Jazari is probably referring “On the construction of water clock” – كتاب أرشميدس في عمل البنكامات. This book was attributed to Archimedes, but its source is unclear. This reinforces al-Jazari statement in the introduction:

“I have studied the books of the earlier [scholars] and the works of the later [craftsmen] –masters of ingenious devices with movements like pneumatic [movements], and water machines … I considered the treatment of this craft for a period of time and I progressed, by practicing it, from the stage of book learning to that of witnessing, and I have taken the view on this matter of some of the ancients and those more recent [scholars]. “

The question of openness or seclusion to the world for people of faith is a relevant question even today for Jews or Muslims.    Maimonides, Rabbi Moshe Ben Maimon, the most important rabbinical arbiters in Jewish history, and polymath, scientist, and  physician lived almost in the same time frame in Cordoba, far away from Diyarbakir in Anatolia but he was a part of the same  Muslim world. During his medical studies, he was introduced to the writings of Aristotle in natural science and did not feel any threat to his faith. He even wrote:

” Consequently he who wishes to attain to human perfection, must therefore first study Logic, next the various branches of Mathematics in their proper order, then Physics, and lastly Metaphysics.” Guide for the Perplexed

It’s amazing to read when today Orthodox Jewish children are forbidden to learn mathematics or natural sciences. Al-Jazari, more engineer than a philosopher, does not deal with matters of faith directly, but his faith is embedded in the text. This doesn’t bother him at all to read and learn from pagan scholars.

  • Secondly, in Diyarbakir in eastern Turkey, there are little more than fourteen hours of daytime in the summer and approximately nine hours of daytime in winter. Al-Jazari made a considerable engineering effort ensuring that there would be twelve hours between sunrise and sunset in summer and winter. This is the purpose of the flow regulator which adjust a short hour in the winter compared to the longer hour in the summertime. Time is not an illusion or a pure man-made concept. The Earth orbited the sun before there were humans around and the sunrise and the sunset, as well as summer and winter, were here before we gave them their name. But the perception of time and its measurement are human inventions. If I would have met al-Jazari and told him that a second that was impossible to measure in his time is the basic unit of time and its scientific definition is approximately 9 billion (for those who want precision 9,192,631,770) cyclic switching between two energy levels of the atom cesium. Not only would that he would not understand a word but also would think me really He did not need such precision that did not fit his daily experience. But I use Waze, a navigation application, and we need accurate atomic clocks at this level of precision to bring me to my destination on time. In today world, the concept of time which varies according to the seasons seems far-fetched, but in the world of al-Jazari who knew sundials and water clocks, it made perfect sense.
  • Thirdly al-Jazari made detailed measurements of the water regulator attributed to Archimedes and found it insufficient. Then he explains in detail how he tries to solve the problem without success through trial and error. It’s ridiculous to compare a modern engineer to al-Jazari, but it is delightful to read the report of a very talented engineer more than eight hundred years ago. It turns out that his concerns are not very different from the concerns of a current engineer. From the text, it turns out he did a “literature review” and theoretical calculations (in this case unsuccessful), and plan and perform the experiments. He was also a skilled man who knows copper, bronze and wood and their processing. When al-Jazari explains, for example, how to prepare the main water reservoir, he’s not satisfied with a drawing and selecting material (copper) but explains how to get a perfect cylinder with a precise wooden disk and how to ensure that the cylinder would have the same diameter all along. For the technical reader, it is easy to sympathize with the difficulties and solutions. There is something appealing in this combination of a man of the books, an engineer, a craft master and an artist who we can meet through the pages and the hundreds of years that passed.

The automaton of a slave girl holding a glass of wine and slaves in the Artuqid Palace


It is a decorated wooden cupboard by the king’s side during the feast. It has a door with two closed leaves. Every seven and a half minutes the doors would open and reveal an automaton (a mechanical device made in imitation of a human being) of a slave girl holding in her right hand a glass filled with wine and in her left a small towel. The king takes the glass, drinks the wine it contains, puts the glass back in her hand and, if he wishes, wipes his mouth with the towel. Then he closes the door leaves on her.  This process will repeat itself every eighth of an hour.

We met slaves and slave girls here and here(in Hebrew), but a quick search of the” Book of Knowledge of Ingenious Mechanical Devices ” reveals ten different chapters mentioning slaves or slave girls. This seems a lot! I went to study slaves in the Islamic world in the twelfth century and how similar or different it is from al-Jazari’s book. To my surprise, my journey led me to Cairo Geniza.

Automaton of the Slave Girl, Serving a Glass of Wine”, a folio from Syria or Iraq, 1315

How does it work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in an inclined plane or a tipping bucket can skip those bits. To understand the mechanism, I use a drawing by the book translator Donald R. Hill with my captions. The slave girl became a boy? I guess Hill or his illustrator did not think that gender was important?

A drawing of the mechanism by Donald Hill with my captions

The cupboard is about 1.6 meter (originally six spans, in Arabic شبر or shabr) and width of approximately 60 cm. There is a wine reservoir above the cupboard which is dripping slowly to the tipping bucket below. I already discussed the tipping bucket here. The tipping bucket fills in seven and a half minutes (eighth of an hour) and discharges all at once into the glass in the slave-girl’s hand. The glass becomes heavy enough to lower the hand of the slave which is on an axis, lifting the extension rod from the docking station.

The slave-girl will roll down the inclined plane and pushes the left leaf with her left hand, which is holding the towel like she is offering the wine glass to the king. The king takes the glass from her hand, drinks its contents, and if he wishes, wipes his mouth with the towel. Then he puts the glass back in her hand, presses it down, and pushes the slave girl gently until she docks. This process will repeat itself every seven and a half minutes as long as there is wine in the reservoir.

Slaves and girl slaves in the “Book of Knowledge of Ingenious Mechanical Devices “

In ten chapters of the “Book of Knowledge of Ingenious Mechanical Devices “ slaves are mentioned:

  1. Category I, chapter seven – The candle clock of the swordsman(Hebrew): An automaton of young black (غلام),  with no beard holding a sword to shorten the candle wick.
  2. Category  II, chapter three – An arbiter for drinking parties: An automaton of a young a slave girl ( (جَارِيَة‎) in Wikipedia also a concubine)  with a  bottle and a glass as well as four slave girls in the balcony.
  3. Category II, chapter four –The musical boat: An automaton of a musical boat with a slave holding a jug and goblet, and four slave girls, flute-player, a harpist and two tambourine-players. I believe that they are “qiyan” – educated girls and women who entertained and entranced the caliphs and aristocrats. I already wrote about them here (in Hebrew)
  4. Category II, chapter seven – A slave holding a Fish and a Goblet: An Automaton of a young slave pouring wine
  5. Category II, chapter eight – A man holding a goblet  and a bottle: An automaton of a slave pouring wine into a goblet
  6. Category II, chapter ten –A slave girl emerges out of a cupboard with a glass of wine: (The current post) Automaton of a slave protruding from a cupboard with a glass of wine.
  7. Category III, second chapter- al-Jazari’s motivation to make the automatic pitcher is written explicitly: ” King Salih, may God double his righteousness, 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.”
  8. Category III, third chapter – A  slave who pours water over the king’s hands: An automaton of a  slave who pours water over the king’s hands.
  9. Category III, ninth chapter – A basin of the peacock for washing the hands (Hebrew): Automaton for washing, one with soap, the other with a towel
  10. Category III, chapter ten- A basin of the slave for washing the hands: An automaton of a kneeling slave holding a water pitcher in his right hand

Cairo Geniza and slavery in the twelfth century

Do we know who were the slaves and the female slave? How they were enslaved and what kind of life did they have?

Cairo Geniza (storage) is a large collection of Jewish manuscripts and fragments written between the ninth century and the nineteenth century and preserved in the attic of the synagogue in Fustat or old Cairo. Maimonides, while in Cairo, used to pray in this synagogue, and it is therefore also known as the Maimonides synagogue.

In my ignorance, I thought the Geniza was for damaged Bibles and holy books but apparently because the Hebrew language was considered sacred they saved everything: court documents, bills of sale, and the correspondence of the local Jewish community and more. Craig Perry wrote his doctoral thesis: “The Daily Life of Slaves and the Global Reach of Slavery in Medieval Egypt, 969-1250 CE” based on materials from the Cairo Geniza. This is not the story of the slaves in Diyarbakir palace where al-Jazari worked, but we can learn a lot.

In an undated letter from the Cairo Geniza, a local court in the Red Sea port of Aydhāb (today in Sudan). Two slave women appeared before the Qadi (Muslim judge), one of them testified that they were kidnapped when they went to fetch water at a local well and sold into slavery. The Qadi asked if they were Muslims? Because according to Islamic law, Muslims were ineligible for enslavement. One of the two insisted that she was Jewish and therefore the case was transferred to a Jewish court. The writer of the letter asked for advice from Fustat about how to handle the matter. His decision to consult with associates explains how this document came to be preserved in the Genizah. We don’t know what happened to the unfortunate women but this is an example of how women were enslaved, and there is a wealth of information about buying and selling of individual slaves.

The second way I already mentioned (in Hebrew) is diplomatic exchanges: for instance, the Egyptian historian Al-Maqrizidescribes  large processions of male and female slaves arrived in Cairo from regions to the south, the first one at 1023 CE:

“On Tuesday, when eight days remained in the month the gift of Ibn

Makārim b. Abū Yazīd arrived from Muḥdathah in Aswān, and it was:

twenty heads of horses, eighty fine camels, a number of black [slaves], females and males, a cheetah in a cage, Nubian goats, birds, monkeys and elephant tusks. “

Prestige gifts of slaves were not limited to Nubia. The Fatimid Caliph al-Mustanṣir Billah received gifts of Turkish slaves from the Byzantine emperor Michael IV, slaves, and eunuchs from the Amir of Yemen and slaves the ruler of al-andalus(الأندلس), the Muslim kingdom of Iberia.

The near constant warfare at the edges of the Islamic empire produced a steady supply of prisoners-of-war and  “wholesale” slave trade.

We don’t know if the slaves in the Palace in Diyarbakır came as a gift from another ruler, purchased individually, or captured during a war.

The bills of sale contain a wealth of information that is useful for reconstructing the geography of slavery, Allowing Perry to do the statistics on the origin of slave girls, horrifying as it may sound. Perry found a large majority of Nubian slaves along with quite a few slaves from other sources:

It is impossible to know, of course, the origin of the slaves in the Palace in Diyarbakır but the Geniza documents cover slave trade in the entire Middle East, and it is reasonable to assume that that is was not very different.

When I think of slaves, I think of hard work in the cotton fields or the sugar plantations in South America. The Islamic world of the 12th century was not associated with large-scale agricultural production. The use of domestic slaves reflects the relative wealth and urban nature of the Muslim elite. Families of merchants, judges, scholars, and others were able to purchase slaves to help with raising the children and household chores. This is evident from the Geniza and is very similar to the book of al­-Jazari. All the slaves in the book are part of the Palace household, helping with daily tasks or helping during the feast.

Slave women were frequently used as child-bearing concubines by Muslim men. According to Islamic law, children born to a Muslim master and a female slave were free-born Muslims. The Fatimid  Caliph al-Mustanṣir Billah, already mentioned, was the son of Sudanese slave named Rasad. That was not the situation in the Jewish community where the Rabbinical establishment struggled to deal with the phenomenon, but that’s another story. I completely Ignored the topic of slave soldiers. This is essential to the history of the twelfth century but is not part of al-Jazari’s book.


My deep connection to al-Jazari makes me want to apologize on his behalf because of the casual manner in which he relates to slavery. It is more painful due to human rights situation in Israel and the general feeling that human rights are under attack.

This is childish; you can’t throw me and the education I received at home and in  Hashomer Hatzair” (a Socialist-Zionist, secular Jewish youth movement) to the 12th century. While I was searching for information on slavery I found  a text by Benjamin of Tudela  which for me was always just a happy song  (in Hebrew) by “HaGashash HaHiver”, an iconic Israeli comedy trio:

” And from there (Aden) to the region of Aswān is a journey of twenty days through the desert. This is Sebā on the Nile River that descends from the land of Kush. There are some among the Kush who have a king and they call him the sulṭān al-ḥabash. There is a people among them that are like animals that eat the grasses that grow on the bank of the Nile and in the fields. They go about naked and lack the intelligence of human beings. They lie with their sisters and with anyone they wish. (Sebā) is very hot. When the people of Aswān go raiding in their land, they carry with them bread, grain, raisins, and figs. They throw this toward (these people), who come to get it. They obtain many prisoners and sell them in Egypt and all of the kingdoms around them. These are the black slaves, the sons of Ham.”

This is more documentation (?) of capturing slaves in Nubia, but the reference to slaves is chilling and I’m afraid that it tells more about Benjamin of Tudela and his lack of ability to see another human suffering then it tells about the poor enslaved Africans. I would like to conclude with a line from the Universal Declaration of Human Rights:

“All human beings are born free and equal in dignity and rights. They are endowed with reason and conscience and should act towards one another in a spirit of brotherhood.”

universal declaration of human rights, December 1948


Formulas are holy and the automaton of a standing slave holding a Fish and A Goblet

“Troubles overcome are good to tell” – “Ibergekumene tsores iz gut tsu dertsyln.” Yiddish proverb by Primo Levi, “Periodic Table


The automaton is one of the simpler al-Jazari’s designs, but the description, like many other descriptions in the book, is intriguing not to say mesmerizing.

“He is a standing slave, ten years old in appearance, dressed in a short jacket with a rob underneath it, and a cap on his head. In his right hand is a glass the fingers curled around the bottom of the glass so that it can be taken out of his hand and put back… His left hand is in the same position, but higher than the glass, and holds a silver fish.”

Drawing of the Automaton with the fish and the goblet, Topkapi, 1206

The fish is surprising.  As far as I know, the fish is a Christian symbol, because of the miracle of the five loaves and two fish, because fishermen like Simon, Peter, Andrew, and John were the followers of Jesus later to become the apostles. Ichthus (Greek ΙΧΘΥΣ) the fish symbol is an acronym for Iēsous Christos, Theou, Yios, Sōtēr; in English:”Jesus Christ the son of God, Savior” has become a sign of recognition among persecuted Christians. The connection between wine and fish reminded me of a fascinating conversation between in varnish makers in the story “Chromium”  from the book “The Periodic Table”  written by Primo Levi; I will elaborate below.

How does it work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in copper hammering or tipping bucket can skip those bits.

This chapter has only one drawing, the one that appears above. Perhaps because this automaton is so simple. On the other hand, there are detailed explanations on the fabrication process:

“If the craftsman is not competent enough to make the face by hammering he can make [various] parts thicker with lead, e.g. the nose, etc.”


“The craftsman should not be afraid that the slave will tilt in any direction. I made him and placed the soles of the feet on the ground, and was afraid that he would tilt, but when he was standing erect he did not tilt at all.”

I took the liberty to take the original drawing of  al-Jazari and make it more like a contemporary drawing which clarifies the mechanism of the automaton:

The mechanism of the automaton, a slave with a goblet and a fish. My drawing

The upper part of the automaton, the head, and the chest is a wine reservoir. Its filling opening is hidden under the cap of the slave. At the bottom of the reservoir, there is a small drain above a tipping bucket. Al-Jazari often used tipping buckets. We met them already here (Hebrew), and we will meet more in future posts. Initially, the tipping bucket is leveled, as shown in the drawing, but after seven and a half minutes it is filled with wine towards its tip, and the bucket tilts and discharges all the wine through the pipe to the hollow silver fish. The silver fish is mounted on an axle, and its lower part is slightly heavier, so the fish is tilted upwards. With the wine,  the fish head becomes heavier and sinks until it is near the goblet and the wine flows into the goblet. Under the weight of the wine, the arm of the slave descends as if he were offering the glass to the king. The king takes the glass, drinks from it, and returns it to his hand, which has risen to its previous position. This repeats every seven and half minute intervals until the reservoir is empty.

“Chromium” by Primo Levi or removing the onion from the varnish

Primo Levi, a wonderful Italian author, his best-known works are related to his personal life story as a Holocaust survivor like “If This Is Man”, “The Truce” and others, but I particularly like the “The Periodic Table”. In my defense I am (also) a chemist  and Primo Levi himself wrote:

“I write because I am a chemist. My trade has provided my raw material, the nucleus to which things join … Chemistry is a struggle with matter, a masterpiece of rationality, an existential parable … Chemistry teaches vigilance combined with reason.”

Many of my students of chemistry, physics and computational science, to their surprise I should  say, heard me over the years reading the story “Chromium” from “The Periodic Table” which opens:

“The entrée was fish, but the wine was red. Versino, head of maintenance, said that it was all a lot of nonsense, provided the wine and fish were good; he was certain that the majority of those who upheld the orthodox view could not, blindfolded, have distinguished a glass of white wine from a glass of red… Old man Cometto added that life is full of customs whose roots can no longer be traced… I made a rapid mental review to be sure that none of those present had as yet heard it, then I started to tell the story of the onion in the boiled linseed oil. This dining room, in fact, belonged to a company of varnish manufacturers. “

The story begins in a prescription book for varnish. Advice is given to introduce into the boiling oil two slices of onion, without explanation or purpose and ends with ammonium chloride in a chromate-based anti-rust paint. For those who do not speak “chemistry” as a native language both are absurd. The weird and wonderful story is the essence of what is science and technology. I will explain the story of the onion, briefly but one who wants really to indulge in the story should read “The Periodic Table”. The onion was inserted into the oil before thermometers were used. When the onion started frying it indicated the proper temperature was reached and it is time to end the boiling process. Over the years varnish manufacturers switch to thermometers but forgot the original reason for using the onion and did not dare to deviate from the recipe they knew. This is how the recipe found its way to the book. When I read about the automaton of al-Jazari, I remembered this conversation and was wondering if they drank from the fish white or red wine?  What do we know about the drinking habits in the twelfth century? Apparently quite a bit.

Drinking habits in the twelfth century

For many years diners were isolated from wine drinking sessions. In ancient Greece, the Symposium (Greek: συμπίνειν, = to drink together) was a feast which took place after dinner. Drinking for pleasure was accompanied by music, dancing, or a good conversation. The modern use of symposium as an academic scholarly discussion is quite different. Although the Romans drank during dinner, wine mixed with water, they had a separate drinking party (comissatio) after dinner. Similarly, Arabic-Islamic culture in the middle ages enjoyed wine only after finishing the meal. In the chapter on alcohol consumption in medieval Cairo, Paulina Lewicka, from Warsaw University, wrote about drinking sessions called majlis al khmar (الخمر مجلس) literally the wine council. The second category of “The Book of Knowledge of Ingenious Mechanical Devices ” is dedicated to “Vessels and Figures Suitable for Drinking Sessions.” In all ten chapter, every chapter covers one device there is not a single meal. It seems that in the palace in Diyarbakir the meals were separated from drinking parties. This makes the question which wine goes with a fish irrelevant. It is still interesting to know what kind of wine they’re drinking? In the chapter of the automaton of the slave holding a fish and a goblet, it  “clarified wine” (sharab murawwaq) is mentioned. “Clarification” is the processes by which insoluble matter, like dead yeast cells, or various tannins, is removed before bottling, thus improving the wine quality and taste. Today this is part of the standard process, and this tells me very little about the actual wine they drank. In 1169 Saladin, already mentioned, became a Vizier in Cairo. He repented wine-drinking and turned from frivolity to religious life and later prohibited drinking alcoholic beverages altogether. Although the Artuqid ruler were vassals to Saladin, the prohibition was not implemented in Diyarbakir. In Cairo things were not simple either. While I was looking for information about wine drinking in this period, I found Firuzabadi’s “Wine-List.” This manuscript from the British Museum’s collections originated in 15th century Cairo. The author is careful to emphasize that he composed it in loyal support of the prohibition. By accident or intention the sub title is quite ironic: “The Cheery Companion, on the prohibition of old wine”  Then he alphabetically names 357 (!). The majority are very descriptive, ” the golden “,  “cock’s eye”, “mother of vice” and  even ‘the one which is drunken in the morning.” Even though it is difficult to know how similar or different the wines in Diyarbakir were in comparison to what we drink, we can conclude that in Diyarbakır palace they probably had a fine selection of wines.

The passing of time and great truths

Back to Primo Levi; The use of oil of Sandarac, a varnish obtained from the small cypress-like tree appears many times in the “Book of  Knowledge of Ingenious  Mechanical Devices “. The idea of using onions to evaluate the temperature of the oil was certainly within reach of al-Jazari. Perhaps he would have enjoyed the story about the onion in the recipe even after precise thermometers were used. The story of the ammonium chloride was probably incomprehensible for him. First chromium was discovered in 1797 by the French chemist Louis-Nicholas Vauquelin, and the use of chromium in the paint industry would be strange. Secondly the “detective story” is based on chemistry that he could not know; Elements, Atoms, Acids and Bases belong to the future, centuries after his time. However, I think he would sympathize with the sweet sensations felt by Primo Levi (details in the story!) when he understood that ammonium chloride the formula is the result of his own work two decades ago. He wrote:

“But formulas are holy as prayers, decree-laws, and dead languages, and not an iota in them can be changed. And so my ammonium chloride by now completely useless and a bit harmful, is religiously ground into the chromate anti-rust paint on the shores of that lake, and nobody knows why anymore.”