Author: אבי גולן

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The Perpetual Flute, control, and knowledge sharing

Introduction

The Book of Knowledge of Ingenious Mechanical Devices contains four perpetual flutes. On the first one I wrote here, the current post is about the remaining three flutes. Each flute has a single page in the book, in comparison the Elephant Clock which takes twenty-two pages and the Castle Clock who is the champion with forty-one pages! The flutes are much simpler and are based on a single principle of compressing air in water containers to creates the sound. The name “flute” is somewhat misleading, and a whistle might be more appropriate as no fingering or an ability to change the pitch(sound frequency).  Some alteration is achieved through the use of two flutes (two whistles), each with a different sound. The uniqueness of each perpetual flute is the way al-Jazari control switching between the two flutes, and this is the main focus of this post.

Three perpetual flutes, left of the tilting buckets, center balance and on the right floats. Topkapi manuscript, 1206.

Fine technology and control theory

A considerable part of the work of al-Jazari falls in the category of fine technology. The term “fine technology” historically, embraces a whole range of machines for various purposes: water clocks, automata, astronomical instruments (not al-Jazari), and more. Some were intended to measure time or for other scientific needs, some for fun and amusement. What was common to all these devices, is a considerable engineering skill and subtle use of mechanisms and control systems. Control theory deals with dynamic systems (change over time) and how their behavior depends on feedback. This is a very wide field with applications from biology to robotics. The control theory contains heavy mathematics that scares students at the Technion and dates from the 19th century ~ seven hundred years after al-Jazari.

Despite mathematics, the control questions remain identical from the 12th century to the present day. It’s easy to think about air conditioning. When We define the desired temperature, the air conditioner will continue to cool as long as the room is above the set temperature and stop its operation when the room is at the right temperature. Although it sounds simple, the control of the air conditioner requires differential equations, and it is relatively complex. Al-Jazari had no electronics or detectors, but the same exact task. There is no difference between activating and stopping the air conditioner and activating and stopping the “perpetual flute.” The four perpetual flutes are a comprehensive class, with demonstrations, in the possible control methods for a 12th-century engineer.

How does it work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in tilting pipes and floats can skip those bits. The three flutes are identical in all their components except the control system. All three of the perpetual flutes have a permanent water supply. In all cases, there are two water tanks to which two flutes, or more precisely whistles, are attached. All the water tank are being emptied using a siphon. There’s an explanation of a siphon here. It almost seems like al-Jazari has prepared a lesson on control systems, so he made sure that all other elements are identical. In all three flutes, the water flows into a bowl welded to a pipe or a tilting apparatus. The pipe is slightly heavier on the right side, and the water flows towards tank B and fills it. The air that was in the tank is compressed out through flute B, which makes a whistling sound. When the tank is full, the control system will transfer the flow of water to tank A, and the siphon will empty tank B. This process repeats itself as long as the water flows.

  1. Perpetual Flute with tipping buckets. We have met the tipping buckets several times, for example, in “The fountain that changes its shape” or “The automaton of a standing slave holding a Fish and A Goblet”. The tipping bucket (in red) is balanced, as you see in the drawing. When it is full, according to the sketch it will happen at any minute, the weight of the water at the front-end is heavy enough to make the tipping bucket swing, and the rod (marked) will push the bowl upward so it would tilt to the left and water would fill the other tank
  2. Perpetual flute with balance controlThe tilting pipe has two openings. The main opening fills Tank, A as can be seen in the drawing below. The secondary opening is smaller, and the water flows diagonally to the balance pan. This is a classical scale, and the weight of water in a bowl will pull the tilting pipe in its direction. When Tank B would be full, the weight of the water would be enough to turn the tilting pipe to start filling tank A.  to fill the container in. Pay attention to the dish attached to the bowl and make it empty its waters.

  1. Perpetual flute with buoys

Each of the tanks has a buoy chamber. When the water rises in the buoy rises with them, and the rod attached to it will cause the tilting pipe to reverse the direction of the flow of water, and the water flows toward the other tank.

Generosity of Knowledge

At the end of the book, al-Jazari writes:

“In this five chapters [a little strange, there are six categories in the book, I have not seen anyone who discussed this discrepancy?] I have described roots which have many branches and great usefulness. When the descriptions are mastered, from them many more [things] may be created. I have omitted to mention many devices which I invented, for fear of obscurity or ambiguity. In what I have mentioned there is information for him who seeks information and profit for him who has zeal.”

I think that al-Jazari wrote these lines personally to me. Al-Jazari’s address bore fruits. The book in general, and these chapters specifically are written for a future reader who would like to learn and build the machines.

  1. Al-Jazari was ahead of his time in his willingness to share knowledge. The Cathedral of Vasily the Blessed is one of the most famous monuments in Moscow. It was built in the sixteen century on orders from Ivan the Terrible. The architect was probably Postnik Yakovlev. According to the legend, Ivan the Terrible blinded Yakovlev so that he could never build anything so beautiful again. It is unclear whether the legend is true, or just a myth, but the desire to preserve knowledge, or ability, is familiar to all of us from the workplace or the university or at least from the literature and movies. Al-Jazari is the opposite. He really went out into the world with a passion to share his knowledge. In this way, he is a magician of engineering, who broke the oath of magicians and brought the hidden knowledge to all mankind.
  2. The world as a whole assumes that “knowledge is money.” It can be seen in the payment we charge for consulting, in the patents industry and more. There is a secondary alternative stream in which people and companies are willing to share free knowledge for their enjoyment and joy of sharing. The open-source movement, the makers, centers in the community or Wikipedia are just a few examples. How to maintain this, what is the model of existence is a complex question that did not bother al-Jazari, an engineer in Saleh Nasser al-Din’s Artuqid Court.
  3. I do not know about the attempts of building machines from the book in seven hundred years since his writing, but quite many attempts to realize al-Jazari’s vision in the 20th century and the 21st centuries. You can read about restorations here. In all cases, the mechanisms, the machines worked wonderfully. I am building the elephant clock from Legos [Hebrew] these days and hope that I will continue this tradition.

 

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Two additional basins for bloodletting and what can we know about al-Jazari’s education?

Introduction

Al-Jazari described four basins for measuring the amount of blood during bloodletting. I already covered two of them: The basin of the monk was explained here with some background on the history of bloodletting, and I explained The Basin of the Two Scribes here with a discussion on the uniqueness of al-Jazari in comparison to other tools for bloodletting. The remaining two: The Basin of the  Reckoner (الحسيب -alhasib) and the Basin of the Castle are almost identical in their mechanism to those explained. The main difference is how the cumulative amount of blood is displayed. This made my mind wander further, and this time what can we know about al-Jazari ‘s education?

The Basin of the Reckoner, dispersed manuscript, 1315, the Museum of Fine Art, Boston.

What do we know about al-Jazari’s education?

We don’t know anything about al-Jazari’s education apart from what he himself wrote 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 for the constant and solar hours, and the transfer by bodies of bodies from their natural positions. I have contemplated in isolation and in company the implications of proofs. 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]. I was fervently attached to the pursuit of this subtle science and persisted in the endeavor to arrive at the truth. The eyes of opinion looked to me distinguish myself in this beloved science. Types of [machines] of great importance came to my notice, offering possibilities for types of marvelous control”

Beyond these lines, we have no information about his education or teachers. However, he was an avid reader who read quite a bit. I wrote about the library of al-Jazari here. His mathematical knowledge, at least according to the book, is limited. I wrote about it here. He is a diverse craftsman in a way that is almost impossible today; he was designing in metal, wood, and paper pulp. He worked with a large number of metals: iron, bronze, copper, brass, silver, and gold. He worked in a wide range of techniques: soldering, casting and hammering and produced himself pipes and gears. In fact, other than the raw materials, he does everything himself. The Makers movement, which is an umbrella term for independent inventors, designers, and tinkerers who preferred to be makers instead of consumers, could use al-Jazari as a role model.

What do we know about medieval education?

From the 8th century AD, elementary schools became generally adopted between the ages of six and ten. The classes were sometimes held in a shop or private houses, but more often in a mosque or building connected to it. The base for learning was the Quran. The pupil copied a passage of the  Quran on his board, and only after he had memorized it, moved to the next passage. We should remember that Muslims believe that the Quran was orally revealed by God to the final Prophet, Muhammad, and not only the Quran is the basis of the religion of Islam, but also a guideline for worship, the book of laws and an instruction book for the proper behavior. It was relatively common to see a procession in honor a ten years old child as a reward for studying the entire Quran by heart.

In addition to the Quran, the students learned the Five Pillars of Islam, including the ritual washing and the prayer. The non-religious teaching elements included verses of poetry as a model for writing and something about numbers and calculations. The schools were intended for all, and initially, no payment was collected for religious reasons. Over the years, it has changed, and the schools have received gifts, food, and money. At the end of the Umayyad Caliphate ((اَلْخِلافَةُ ٱلأُمَوِيَّة‎ in the 9th century, there is evidence of a school that contained 3000 pupils, it is clear that such an organization cannot operate without resources. Al-Jazari likely studied at this kind of school.

When the student completed the four compulsory years, he could go on for another three more years in which he studied grammar, rhetoric, and literature as well as the history of Islam. There are no references to literature or history in Al-Jazari’s book, and it is difficult to know if he continued his studies beyond the first four years. I didn’t find a medieval painting, but the contemporary photograph of Muslim pupils who are memorizing the Quran is probably quite similar to the 12th century:

Muslim students study the Quran in the mosque in India

After the four years of compulsory education, most of the students worked with their parents in the fields or were sent to work with a master craftsman as an apprentice. The work as an apprentice was conducted in small workshops of the bazaars(بازار). The bazaar is a network of narrow streets,  wide enough for a loaded donkey to pass through, usually covered with a wooden roof or some shaded areas, in which the workshops simultaneously created and sold their merchandise. The workshops were organized by guilds. Bernard Lewis, the historian who specialized in oriental studies, wrote the most authoritative work on Muslim guilds. He claimed that “guilds are one of the most interesting and characteristic phenomena of medieval Muslim civilization.” They are not merely equivalent of the European guilds, but so important was the guild in Muslim life, that in many cases the very topography of the Muslim city was determined by the needs of the guilds. From Morocco to Java, with surprising uniformity, the Muslim town rose around three or four central points, always the same. The first fixed point is the exchange. Around it is the toll-gatherer, the local mint (where there is one), the auction market, and the Muhtasib, or inspector of markets. The second center is the Qaisaria, a strong, closed-in building where foreign goods and valuables are stored. The third is the thread-market (Suq al Ghazl), where the women come to sell their own handiwork. And here, too, are the commodities women are likely to buy- butchers, bakers, etc. The fourth center is the university, usually attached to a mosque. Around these four centers are distributed the guildsmen; each guild in its own market.

At the head of the guild is the Sheikh. He is elected by the master craftsmen. Once selected, he was the unchallenged ruler of the guild, combining the functions of CEO, Treasurer, responsible for the taxes for the authorities responsible for the festivities and the concern for the sick and the poor. After him in hierarchy came elders among the master craftsmen, and next come the master craftsmen, the main body of the guild and finally the apprentices. The rank of a journeyman, skilled workers that have completed official apprenticeship qualification but may not yet work as self-employed master craftsmen so essential to European guilds, almost did not exist.

The apprentice (Mubtadi – مبتدئ) was taught by the master’s decision, for an unspecified period of time and without a specific curriculum. Some sources mention 1001 days that sound more like a ceremonial period than a three-year training. As the Apprentice training began at age 11, it was unlikely that they become independent craftsman at the age of 14. In most cases, the apprentice had to demonstrate his ability by producing a particularly complex piece of art (in Lewis’s words “masterpiece”), and then the master decided that the apprentice period was completed. The apprentice did not usually get paid during the apprenticeship, but the master did take care of their needs. Al-Jazari, unfortunately, does not write anything about this period of his life. I am pretty sure he went apprenticeship, and I would be very interested to know how was the experience.

It is impossible to talk about vocational education in Israel without entering a minefield. For many years, the youth of Edot HaMizrach (descendants of Jewish communities in the Middle East and North Africa ) were sent to vocational education( welding, metalworking, or barbershop training) regardless of their qualification. Only a highly detached consultant could send the deceased Ronit Matalon [an Israeli writer], with her amazing Hebrew to vocational education, and there are certainly many more examples.

However, the combination of vocational schools and apprentice training has many advantages. Germany, Switzerland, Denmark, as well as other countries have been demonstrating for years how vocational education can produce master craftsman that can not be replaced. I went to a traditional high school, and from there to the university and never, not even in Santa Clara or Portland, I didn’t feel that my education was short in comparison to the finest engineers in the world. Even so,  sometimes I want to go back and be the apprentice of al-Jazari and learn by doing and watching the very best.

 

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The Candle Clock of the Swordsman

Introduction

Candle clock is an ancient device for measuring the passage of time. The earliest reference is a Chinese poem by You Jiangu (AD 520). It appears in Wikipedia and other places, but I couldn’t find the poem itself, any help would be appreciated. These were simple clocks that were based on the relatively stable burning rate of candles. Linear graduation specified the elapsed time. All four candle clocks by al-Jazari are complex, full of inventions, a daring leap comparing to the classical candle clocks. In the clock of the Swordsman, the falcon emits a bronze ball every hour, so that the number of accumulated balls indicates the number of hours passed from sunset, at the same time the swordsman swings his sword and clips the top of the wick.

The Swordman Candle Clock, a Manuscript from 1315 Syria.

How does it work?

Al-Jazari opens the chapter of the candle clock of the swordsman with these words:

“I say that I have never come across a work by anyone on candle-clocks and have never seen a completed [example of such a] clock. I heard tell, however, of a candle-holder with a brass candlestick on it in which was a wax candle whose wick went through a hole in a cross-piece at the top of the brass candlestick. Near the foot of the candlestick was the head of a lion. When a constant hour had passed from the lighting of the candle, a ball fell from the mouth of the lion.”

The clock al-Jazari built was his version to the clock in the tale. The technical explanation, as always, will be colored in blue, so anyone who is not interested in balancing weights or bayonet mounts can skip those bits.

On the right side, the swordsman clock, Topkapi manuscript, 1206, with my explanatory captions. On the left is a three-dimensional sketch of the same clock based on the drawing by Donald Hill.

The massive candle, a height of about 40 centimeters (a span- شِبْر and a half) and almost four centimeters in diameter is standing on a cast bronze base. On the base, there is a brass sheath. The sheath is not a perfect circle but has two “lips” forming the ball channel, containing fourteen bronze balls. The candle alone blocks the balls. A heavy balancing weight of ~ 1.2 kg is connected through a pulley system. The weight guarantees that the bronze base and the candle are being pushed upward all the time. The length of the candle prevents the base from rising. The burning rate of the candle is measured meticulously, and the height of the candle is calculated so that it is suitable for sixteen hours of combustion, in practice, it would only burn for fourteen hours.

When the candle is lit at nightfall, the fire melts the wax, and after one hour the candle is shorter by 1/16. The weight will go down by this amount, and the base would go up, and the candle does not block any longer the lower ball. The ball is released and falls into the pouch attached to the string which is connected to the extension of the hand of the slave. As a result, the slave strikes the wick with his sword and cuts off the burnt-away section. The ball then rolls down and goes into the falcon’s head and then falls into the pedestal of the candle-holder. This happens at every hour until the end of the night

The part of the black slave and his sword is less detailed in my opinion, and its construction will require more experimentation and adjustments. Al-Jazari himself warns the reader that ” This movement [was perfected] after arranging and calculating and [after] repeated trials.”

Al-Jazari worked in the 12th century almost six centuries before Joseph Priestley discovered Oxygen, wax chemistry was also unknown at his time, and so was the understanding of Capillary Action. Despite this, his strong understanding of various materials, from working and experimenting, brings him to a few insights that we can now explain with the science we have learned. For example, al-Jazari requested that the candle will be made of pure wax. Candles can be prepared from natural fat, beeswax, whale fat, oil derivatives, and more. The rate of combustion depends on the combustion material, and as the material is more uniform, the rate of the combustion will be more uniform. He determines the weight of the wick, six grams. The wax is rising in the wick by capillary action, and therefore, various wicks will have different burning rate and would alter the time measurement.

One last thing, quite insignificant for the clock but interesting never the less. The candle cover was designed to replace candles comfortably. This method of mechanical attachment is known as “Bayonet mount,” and despite its exotic name, it is a useful technique of attachment  to this day, for example in camera lenses or electric lights and includes a cylindrical male side with one or more radial pins, and a female receptor with matching L-shaped slots and with spring(s) to keep the two parts locked together:

The source of the peculiar name is the use of soldiers in this type of connection to quickly attach bayonets at the ends of their rifles, but the first documented bayonet mount is undoubtedly al-Jazari book in this chapter.

My chemistry teacher and Michael Faraday

In 1972, I was sixteen and studied in the Tichon Hadash in Tel-Aviv. It was the only year we studied chemistry. To my shame, I do not remember the name of my teacher, even though one of her classes is engraved in my memory as an extraordinary experience that affected me deeply. We were the second class to start our high school in the seventh grade before there were middle schools in Israel, we went through screening exams, and we were smart, at least in our own eyes and smugly knowledgeable. When the teacher said:  “We would learn today about the candle.” The class broke into laughter; it seemed childish and not “scientific” enough for us. I’m afraid I’ve been among the laughing. Pretty soon she asked why the wax was burning up the wick and not burning in the candle? At once, in a fraction of a second, as in a revelation, I understood three things:

  • First, that despite my laugher, I do not understand the candle burning at all.
  • Secondly, there is a fascinating science in the most trivial things around us, like candles I have known well from Chanukah ceremonies and Shabbat candles.
  • Third, I don’t ask questions, which If I were the young man I hope to be, I would ask.

That’s a lot for a single lesson. My chemistry teacher knew nothing about the internal storm  I went through, and after years when I became a teacher myself, I thought about this lesson and I was hoping that sometimes I get to my students even when I don’t necessarily know about it.

When I worked at the Davidson Institute, Dr. Oved Kedem, my friend, introduced me to a thin book:

Six lectures on “The Chemical History of a Candle” that Michael Faraday gave at the Royal Institute in London in 1848 as part of the tradition of Christmas lectures for young people.

Michael Faraday was an English scientist, one of the best experimentalists in the history of science with an unusual life story. He was born into a poor family in London and was forced to help support the family as an apprentice in a local bookbinder and bookseller shop at age fourteen. He acquired all his education by reading books that were in the shop. The beginning of his scientific career was in popular lectures by Sir Humphry Davy, the president of the Royal Society at the time, so that his Christmas lectures were closing a circle. You can find the original book here. Those who do not want to deal with the original text can watch the series of short films done by Bill Hammack to present and explain Michael Faraday’s lectures.

On the fourth page, Michael Faraday answers the question  of my chemistry teacher:

 “Then there is another point about these candles which will answer a question—that is, as to the way in which this fluid gets out of the cup, up the wick, and into the place of combustion. You know that the flames on these burning wicks in candles made of beeswax, stearin, or spermaceti, do not run down to the wax or other matter, and melt it all away, but keep to their own right place. They are fenced off from the fluid below, and do not encroach on the cup at the sides. I cannot imagine a more beautiful example than the condition of adjustment under which a candle makes one part subserve to the other to the very end of its action. A combustible thing like that, burning away gradually, never being intruded upon by the flame, is a very beautiful sight, especially when you come to learn what a vigorous thing flame is—what power it has of destroying the wax itself when it gets hold of it, and of disturbing its proper form if it come only too near.”

This booklet is a real gem, and I met it much more experienced, after completing three degrees in science, but I was still fascinated and surprised by the opening sentence  that opened the lectures, and I think that al-Jazari would be curious too:

“There is not a law under which any part of this universe is governed which does not come into play and is touched upon in these phenomena. There is no better, there is no more open door by which you can enter into the study of natural philosophy than by considering the physical phenomena of a candle.”

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The peacock which discharges water from its beak and peacocks as a symbol

אַז די פאַווע קוקט אויף אירע פֿעדערן – קוועלטזי, אָבער אַז זי קוקט אויף אירע דאַרע פֿיס- וויינט זי”

“When the peacock is looking at its feathers she (in Yiddish peacock is always feminine) is happy and when she looks at her scrawny legs she cries”)

Introduction

The Peacock who discharges water from its beak to perform the ritual ablution is the sixth Peacock that we encounter in al-Jazari’s book; four peacocks in the water clock of the peacocks and another one in the basin of the peacock (in Hebrew). It’s time to talk about peacocks and many thanks to Dr. Shoey Raz that his comment sent me to this journey.

The peacock which discharges water from its beak. Topkapi manuscript, 1206.

How does it work?

The technical explanation, as always, will be colored in blue, so anyone who is not interested in siphons can skip those bits. The hollow peacock is quite similar to in the Basin of the peacock, which was already explained. It is made from copper large enough to contain the water needed for the ablution washing. Its curved neck is a siphon. A siphon is a tube in an inverted “U” shape, which causes a liquid to flow upward, above the surface of a reservoir, with no pump, but powered by the pull of gravity. I wrote more on siphons here. The peacock is a water container, hollow as far as the beginning of its neck. The tail is divided halfway up by a plate, so that the upper half of the tail forms a separate chamber, while the lower half is connected to the main reservoir. Al-Jazari made a secret plug with an extension which reaches to the top of the peacock’s tail. A siphon would only work when the water in the peacock reservoir reaches the bend of the siphon. Water is poured into the belly of the peacock until it rises to a point beneath the curve.  To start the ritual ablutions, a servant puts it down on a handsome pedestal in front of the king, rotates the valve slightly, the valve opens, and the water from the upper chamber flows into the peacock’s belly, and water flows through the siphon into the peacock’s beak and the ablution ceremony begins.

The peacock as a symbol

The Peacock is a native Indian subcontinent and serves as the national bird, but he has a long history in the Middle East. The Greeks discovered the Peacock following the conquest of Alexander the Great. However, they still managed to insert it into the Greek myths:

In one of his attempts to hide his infidelities, Zeus turned his lover, a water nymph named Io to a beautiful white Heifer. Personally, I find it a little insulting although Hera connection to the cow symbol is ancient and has to do with being the goddess of motherhood and fertility. Hera, who suspected (rightfully so!) the Zeus is chasing other women again, begged Zeus to give her the heifer as a present, which, having no reason to refuse, he did. Hera then sent Argus, a giant who had 100 eyes, to watch Io and prevent Zeus from visiting her. Argus’s eyes turned him into the ideal guard – while some slept, others were awake and open. Zeus sent Hermes to distract and eventually slay Argus and Hera transferred all his eyes to the tail of a peacock to thank and honor her loyal servant. The importance of Peacock in legends and myths is understood. The green, deep blue colors, won him the admiration and awe. The “eyes” on the tail were seen as a sign of comprehensive vision and wisdom.

I heard of the Yazidis only because of the horrible genocide by ISIS, but they have an exciting and unusual religion. According to their creation story, God was originally “over the seas,” a notion reminiscent of the Biblical passage: “And the Spirit of God moved upon the face of the waters.” playing with a white pearl. The pearl was broken and became the substance from which the Earth and other planets were formed. Then God created Tawûsê Melek (in Kurdish: طاووس ملك) translated to English as Peacock Angel with six other angles known as ‘the Seven Mysteries.’ All seven are part of God and not separated from him, fragments of God’s light, like Rainbow colors, are the light refractions. Tawûsê Melek is associated with the blue color while at the same time is the source of all other colors/angels. When Tawûsê Melek came to earth, the Peacock was(is?) the physical embodiment of the Rainbow. You can read more on the Yazidi religion and the Peacock Angel here [in Hebrew].

In Islam, there is more than one perception of the peacock. Some claim that the beauty of the peacock tail is a proof of Allah capability to create beauty to satisfy men passion for grace, and they rely on the Quran, Surah 35:27:

“Do you not see that Allah sent down water from the sky with which We brought forth fruits of diverse hues? In the mountains, there are white and red, of diverse hues, and pitchy black; and human beings too, and beasts, and cattle? Diverse are their hues. From among His servants, it is only those who know that fear Allah.”

It’s amusing to know that Charles Darwin, the father of evolution, was confused by the beauty of the peacock tail and thought (in error) that this contradicts or at least not support his theory of evolution. In a letter to Asa Gray, an American botanist, he wrote:

“The sight of a feather in a peacock’s tail, whenever I gaze at it, makes me sick.”

In the Hadith Bihar al-Anwar, a comprehensive collection of traditions compiled by Shia Muslim scholar Mohammad-Baqer Majlesi I found this beautiful tale:

“Glory be to Allah, the King, the Holy. Glory be to Allah, the Great, the Most High. There is no god except Allah, the Living and Self Subsisting. ” Whenever the Angel would say this tasbih [repetitive utterances of short sentences in the praise and glorification of Allah] all the peacocks that are on the Earth would start to praise Allah and open their wings up in respect (of Allah). Whenever this Angel in the heaven would become quiet, the peacocks on the Earth would become quiet. The Angel in the heaven had green hair and white wings, so white that no one has ever seen anything that white before.”

There is also this sermon from Imam Ali, the cousin, and son-in-law of Muhammad, the last prophet of Sunni Islam and the first rightful successor to Muhammad by Shia Muslims which is strangely similar to the Yiddish motto:

“The peacock walks with vanity and pride, and throws open its tail and wings and laughs admiring the handsomeness of its dress and the hues of its necklace of gems. But when it casts its glance at its legs, it cries loudly with a voice which indicates its call for help and displays its true grief, because its legs are thin like the legs of Indo-Persian cross-bred cocks.”

There’s additional material about the Peacock in Islam and other cultures, but I can’t conclude this section without writing that peacocks from India appear already in the Bible:

“For the king’s ships went to Tarshish with the servants of Huram: every three years once came the ships of Tarshish bringing gold, and silver, ivory, and apes, and peacocks.” (KJV Chronicles II, Chapter 9, verse 21)

In Hebrew, the text is “Tukii” which in Modern Hebrew means Parrot. However, most translators and commentators believe that the original meaning was peacocks mainly because, in Tamil, the language spoken in Southeast India, Peacock is named Tukii.

A mosaic from the old synagogue Maon, the 6th-century ad

Did al-Jazari know the Greek mythology story about Io and Hera?  I doubt that very much. Did he know the stories about the Peacock from the Muslim tradition? More likely, but we will never know. Maybe he just liked peacocks? We have only our imagination, and all answers are right.

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

Introduction

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

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

How does it work?

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

Some Math

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

  • Euclidean geometry
  • Analytic geometry.

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

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

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

Circle equation, Analytic geometry

When:

r is the circle radius

a,b are the coordinates of the center point

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

Polymath and al-Jazari, the first engineer

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

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

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

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

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

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

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

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

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The Musical Boat for a Drinking Party

Introduction

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

The musical boat, Topkapi manuscript, 1206

How does the boat work?

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

 

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

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

Qiyan – Musician slave girls

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

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

Musical robot

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

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

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

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

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

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The Drummers’ Clock and Musical Robots

Introduction

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

The Drummers’ Clock, a dispersed copy, 1315

How does it work?

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

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

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

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

Robotics and the student’s disappointment

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

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

Musical robots and music

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

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

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

Some are more complex, but still approachable:

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

Some are borderline science fiction:

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

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

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The basin of the Peacock and the magic of automata

Introduction

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

Basin of the peacock, Topkapi manuscript, 1206

How Does it work?

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

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

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

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

 

Automaton  (self-operating machine) magic

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

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

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

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

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

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

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

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

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The Peacock Clock and the Beauty of Engineering

Introduction

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

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

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

The Peacock water clock, Topkapi Manuscript,1206

How does it work?

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

A drawing of the mechanism with my captions

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

The Beauty of Science and Technology

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

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

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

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

Is The Peacock Clock beautiful without being a machine?

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

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

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

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

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

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

Simplicity

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

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

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

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

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

Power

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

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

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

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

Rube Goldberg self-operating napkin

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

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

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

Qur’an 9:72

The fountain with two tipping buckets, Topkapi manuscript, 1206

Introduction

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

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

A miniature of paradise from the 16th century

How does the fountain work?

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

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

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

Banū Mūsā

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

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

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

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

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

What is the Controversy?

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

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

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

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

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

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

Curiosity and Doubts

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