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What do we know about Al-Jazari? Part 2: School and Training

Al-Jazari does not write about himself except a little, as explained in Part I. There is still quite a bit we can learn about the man from the wonderful book he wrote.

The Kuttab

In the 12th century, the Kuttab (كُطَّاب) was the primary school of the Muslim world. The main purpose of the Kuttab was to teach the Quran: children, mainly boys and occasionally girls, memorized it, learned correct recitation, and acquired basic religious knowledge. The education included reading and writing, verb conjugations, and basic arithmetic, as well as skills valuable for everyday life, commerce, and administration. The emphasis was on memorization and discipline, which often included corporal punishment. Scholars estimate that 15–25% of the male population was literate. Most of them studied at the Kuttab, and wealthy and educated families hired private tutors. The poor, rural, urban, and nomadic classes did not learn to read or write at all. The Kuttab was often a small local institution, sometimes just a room attached to a mosque, a private house, or a shaded shelter under a veranda. The teachers were usually called muʿalm (معلّم). They received a low salary from the students’ families or from the waqf (وَقْف, endowment) that supported education. The students sat on mats and wrote verses from the Quran on wooden tablets that could be washed for reuse. The Kuttab was seen as much a religious duty as an educational tool.

Kuttab, from Maqamat Al-Hariri ( مقامات الحريري), 13th-century manuscript, British Library.

The Mathematical Perspective

Al-Jazari’s education and training can also be viewed from a mathematical perspective. In the 12th century, there were no secondary schools. The few who wished to, and could afford it, continued their studies with the help of private tutors. Mathematics in the Islamic world in the 12th century was a rich and mature discipline, fully integrated into the sciences, engineering, and even Muslim life. Algebra, for example, was used in inheritance law (علم الفرائض), land division, and commercial contracts. As early as the 9th century, Al-Khwarizmi (الخوارزمی) wrote the foundational book on algebra and compiled trigonometric tables. This mathematical culture later passed to Latin Europe, and parts of it became the foundations of science in the late Middle Ages and early modern period.

Let’s consider, for a moment, the elephant clock. The sinking buoy pulls a rope, which rotates a pulley about its axis. On the pulley sits a scribe that indicates the passing minutes. All this will only work if the diameter of the pulley matches the path of the sinking buoy and the length of the rope. This requires the use of geometry and relationships (proportionality). There is not a single equation in the chapter on the elephant clock. There is no use of algebra, Euclidean geometry, or trigonometry. Al-Jazari’s mathematics is not explicit but is found within the machines. Al-Jazari apparently worked by trial and error and the healthy intuition of a craftsman.

A Soviet stamp commemorating the Persian mathematician and astronomer Muhammad ibn Musa al-Khwarizmi

The mathematical background, or rather the lack thereof, supports the claim that Al-Jazari studied in the Kuttab and nothing more.

Apprenticeship

An apprentice is a young person who learns a profession or craft through an apprenticeship with a skilled craftsman, a Master. As part of the apprenticeship, the apprentice serves as an assistant to the craftsman and sometimes even as a servant. In the Middle Ages, throughout the Muslim world, in Christian Europe, and beyond, this was the royal road to learning blacksmithing and metal work, and it is very likely that Al-Jazari studied with such a Master as an apprentice.

Guilds were a central part of the social structure in medieval Western Europe. The entry into a guild was through apprenticeship. After several years of training, the apprentice was qualified as a “journeyman,” a craftsman whose training was complete but who was not yet able to set up his own workshop. The journeyman found their livelihood by working for a daily wage for another craftsman, and by moving among various craftsmen, they helped spread new knowledge and techniques. After several years of work, travel, and experience, a journeyman could be ordained to the rank of a “Master”. We have countless European documents on the subject of guilds and training, including contracts signed between apprentices’ parents and the master who took them under their protection. In contrast, in the Muslim world, apart from a few apprenticeship contracts in the Cairo Genizah, there are no apprenticeship contracts at all; there is no historical evidence for the existence of craft guilds, and there is not even an Arabic term for them. Ultimately, it was Goitein (Shlomo Dov Goitein, the central historian in the study of the Cairo Genizah) who rejected this outright: “There was no such term because guilds in the narrow sense of the word had not yet arisen.”

The historical differences between Western Europe and Islamic countries had little if any effect on the daily life of the apprentice. The vast majority of students who completed the Kuttab, as well as those who did not receive primary education, received vocational training. Children joined their parents in agricultural or urban work or as apprentices to professionals in the workshops of the markets. Even in the absence of written contracts, training began between the ages of 10 and 14. The agreement, even if oral, stipulated that the artisan was obliged to teach the boy his craft (صناعة). Although some of the contracts in the Cairo Geniza are for only a few months. It is clear that no one learns blacksmithing or any other metalworking technique in a few months. In Western Europe, where records exist, the apprenticeship lasted 7 years, and it is likely that this was also the case in Muslim countries. These contracts also specified the master’s duties (training, food, lodging, and often clothing). And the duties of the apprentice with an emphasis on behavioral requirements: the apprentices had to be obedient, loyal, and not “degrade” the workshop. In the Muslim world, these were oral agreements based on Muslim law. Al-Jazari is a very skilled craftsman, and the book is full of details that demonstrate his intimate knowledge of metalworking. For example, when he explains how to make the main water tank for the castle clock, he does not content himself with a drawing and the choice of materials (copper) but details how to obtain a perfect cylinder using a precise wooden disc and how to ensure that the cylinder is the same in diameter throughout. Al-Jazari makes extensive use of iron, copper, bronze, and lead, as well as a variety of processing techniques, such as hammering, casting, and soldering. In the Middle Ages, there was no other way to learn metalworking than through apprenticeship.

Medieval blacksmith at work, 14th century Sloane Manuscript No. 3983, British Library

Al-Jazari – Professional Literature

Al-Jazari’s approach to the professional literature of his time is impressive. In the post on the castle clock, we saw that Al-Jazari knew and criticized the work of Archimedes, and in the post on the fountain with two tipping buckets, we discussed his dispute with the Banu Musa, but the highlight is in the chapter on the perpetual flute, where he cites three sources:

 “I came across a well-known paper by Apollonius, the Indian carpenter: he made a wheel which turns slowly and opens water outlets…”

“I also examined another old instrument, about which I found no written report, but a drawing. In this, the flute is like a nay having eight holes”.

“I [also] examined a paper written in Baghdad in the year 517 A.H. by the eminent inventor Hibat Allah al-Husayn al-Asturlibl, in which he makes a real innovation….

During my time as a teacher at the Davidson Institute for Science Education and in academia, I have seen how difficult it is for students to read an article critically. The fact that Al-Jazari does this regularly is impressive and tells us something about the man.

Mechanical treatises were relatively rare, certainly compared to manuscripts in medicine, theology, or law. The previous important book is by the Banu Musa and contains no such references to earlier sources. In this respect, Al-Jazari is truly groundbreaking, bringing engineering literature closer to classical knowledge. This is all the more surprising since the Banu Musa brothers were educated at the House of Wisdom, a magnificent institution in the heart of Baghdad with a very broad mathematical and scientific education, and Al-Jazari studied only the Kuttab.

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What do we know about Al-Jazari? Part A

We have no information about Al-Jazari’s life except what he wrote himself in the introduction to his wonderful book (Hill’s translation):

” I am in the service of the king al-Salah Nasir al-Din Abi al-Fath Mahmud bin Muhammad bin Qara Arslan bin Dawud ibn Sukman bin Artuq, the king of Diyar Bakr, may God preserve him with those whom He chooses to preserve. That is following my service to his father and his brother, God sanctify their souls, before the kingship passed to him – a [total] period of twenty-five years, the first of them year 577 [Hijri- 1181 AD]. God, may He be exalted, has singled him out with distinctions of intelligence, high-mindedness, justice, and probity, so that he surpasses in justice and probity the kings of the present age, and excels the lords of near and far in beneficence and graciousness.”

In many places, it is claimed that Al-Jazari was born in 1136 and died in 1206. As for his birth, I have not found any historical source, and I fear that this is a complete fabrication. As for his death, we can use the colophon of manuscript number 3472 in the Topkapi Library, the earliest copy of the Book of Knowledge of Ingenious Mechanical Devices. The colophon is a note by the scribe, usually at the end of the manuscript, in which the scribe records details about its creation, such as the date, place, their name, the book’s title, etc. The colophon consists of two parts.

The first part is the testimony (شهادة):

“Its correctness has been attested to, and this book was collated against the handwriting of its author, Badiʿ al-Zamān Abū al-ʿIzz Ismāʿīl ibn al-Razzāz al-Jazarī — may God have mercy upon him.”

The testimony does not state the year of Al-Jazari’s death, but the reference to Al-Jazari (“May Allah Almighty have mercy on him” (رحمه الله تعالى)) is a typical one for someone who has already passed away.

The second part is a classical colophon:

“Praise be to God, Lord of the Worlds, and blessings and peace be upon our master Muḥammad, his family, and companions all together. The completion of the manuscript occurred on 12 Shaʿbān[The eighth month of the Muslim year] 602 A.H.[ [Hijri- 1206 AD]. It was written by the humble servant in need of God’s mercy, Muḥammad b. Yūsuf b. Uthmān al-Ḥaskafī—may God forgive him and all Muslims.”

The book was written in 1206 AD. This is based on the book’s introduction quoted above. Al-Jazari began his work in the palace in 1181 CE and worked there for 25 years. If so, he probably died a few months after completing the book.

When I discovered the Book of Knowledge of Ingenious Mechanical Devices, I looked for additional historical sources on Al-Jazari and his machines, such as a Muslim traveler who passed through Diyarbakir and testified to the machines he saw with his own eyes. Or perhaps a historian or biographer of Muslim scholars who would expand on the limited information from the book’s introduction. I wanted to learn more about the engineer who wrote the book I loved. This is probably naive, although there are still many Arabic manuscripts that have not been translated, or even cataloged, and no one knows what is written there.

During my research, I found famous travelers like Ibn Jubayr (ابن جبير), who left Mosul in June 1184, on his way to Damascus. He passed through the southern outskirts of the Artuqid principality. Ibn Battuta (ابن بطوطة) visited Mardin (ماردين) in 1326 and other places. Also, less well-known travelers such as Abu al-Hasan al-Harawi (أبو الحسان الهروي), who visited the area in 1215, a few years after the death of al-Jazari, and Ibn Shaddad (عز الدين بن شدداد), who wrote extensively about Diyar Bakr. I have written here about Ibn Jubayr’s Travels and Ibn Battuta’s [in Hebrew] Travels. In neither book is there a word about al-Jazari or his machines.

The travelers focused on geography, particularly holy places such as Mecca and Jerusalem. They also dealt extensively with Muslim issues, such as prayer times, mosques, Waqf (وَقْف), and covered political order, including rulers, justice, and security for the inhabitants. They described social customs such as clothing, markets, and food, and sometimes gender norms as well. There are a few reports of wonders (عجائب), but these are mainly natural wonders, such as the tar springs near the Tigris. To the best of my knowledge, there is no one description of clocks or other mechanisms. This is also true of Christian travelers in Western Europe during the Middle Ages. Al-Jazari’s absence from the travel books has more to do with the genre than with him and his machines.

I am more surprised by the complete silence of medieval historical sources. Ali ibn al-Athir al-Jazri (علي بن الاثیر الجزری) was a historian, hadith scholar, and biographer of great importance. His name ends in al-Jazri (الجزری), like the author of our book. The suffix of the name (نسبة in Arabic) indicates the place of origin of the person, his ancestral tribe, or his ancestral origin. In this case, it is the city of Cizre in Turkish Kurdistan, near the Turkey-Iraq-Syria border triangle. Its ancient name is Jazira Ibn Umar (جَزِيْرَة ٱبْن عُمَر). We have a wealth of information about Al-Jazari the biographer, unlike Al-Jazari the engineer, and we know that he was born in Cizre on May 12, 1160 AD. Was Al-Jazari, the engineer, also a Cizre native, or is it just his family’s origin, even though he was born in Diyarbakir? We will probably never know. Either way, al-Athir was a major historian in the Middle Ages, and his book “The Complete History” (الكامل في التارخ) is a seminal historical source to this day. There is no mention of Al-Jazari the Engineer. One could argue that this is due to the book’s organization, which presents a comprehensive, chronological world history, extending from the creation to the time of the Prophet to the time of Ibn al-Athir, with scholars appearing only in the context of a significant contribution to a noteworthy event. But al-Jazari does not appear in the writings of Yaqut al-Hamawi (ياقوت الحَمَوي) or Ahmad ibn Khalkan (أحمد ابن خلكان). The latter was a renowned historian who wrote the famous biographical encyclopedia of Muslim scholars and is considered the most prominent biographer in Islamic history. This silence is especially striking, since Ibn Khalkan lived in Erbil and Damascus, not far from Diyarbakir, in the very same century.

How can this be explained? Humanity needed engineers in ancient times; the Pyramid of Giza or the Aemilius Bridge in Rome were not built without the involvement of someone who is today called an engineer. But unlike philosophers, doctors, or religious scholars, an engineer was not considered a scholar but a skilled craftsman, however talented, and Al-Jazari, although highly respected among his Artuqid patrons, was also seen as an artisan, a craftsman. His legacy survived through his book, not through mentions in chronicles or biographies. It was only in the modern period (19th-20th century), with scholars such as Wiedemann, Hauser, and later Donald Hill, that he was “rediscovered” as a central figure in the history of technology.

All that remains is to turn to the book of Ingenious Mechanical Devices to learn about Al-Jazari, the man, and you can learn quite a bit. Some insights about Al-Jazari are scattered across the blog’s posts. In Part B, I have compiled them into a portrait of the man that emerges from his book.

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Ibn Jubayr and the Artuqids Principality

Introduction

Since I came across al-Jazari’s book, I have been hoping to find a Muslim traveler from the 12th or 13th century who visited the Artuqids’ court and saw with his own eyes the elephant clock and other wonderful machines built by al-Jazari. This is probably a childish fantasy, although there are still many Arabic manuscripts that have not been translated or even cataloged, and no one knows what is written within them.

As I have written before, we are aware of three books that originated from this tiny principality: Al-Jazari’s book, which is the reason for this Blog. A few years before that, Usama ibn Munqidh((أسامة بن منقذ) wrote his book ” The Book of Contemplation  (كتاب الاعتبار), and there is also a third, lesser-known book by al-Jawbarī (الجوبري) called ” The Book of Charlatans ” (كتاب المختار في كشف الأسرار). Three books that have come down to us from a tiny principality in Anatolia represent only a part of the cultural flowering during the Artuqids period. Can we learn anything about the Artuqidss and the principality from travelers who visited it or were nearby?

During my research, I found very famous travelers, such as Ibn Jubayr, who left Mosul in June 1184 on his way to Damascus via Aleppo. He passed through the southern outskirts of the Artuqids principality. In 1326, Ibn Battuta (ابن بطوطة) visited Mardin (ماردين) and other places. In this post, I will focus on Ibn Jubayr, and later, I may write about Ibn Battuta and other travelers I have identified, such as Nasir Khusraw (ناصر خسرو), who was in Diyar Bakr (ديار بكر) in 1046, when it was still ruled by the Marwanids (مروانيون). Abu al-Hasan al-Harwi (أبو الحسان الهروي), who visited the area in 1215, and Ibn Shaddad (عز الدين بن شدداد ), who wrote extensively about Diyar Bakr. This is a map of this part of Ibn Jubayr’s journey:

Map of the Artuqids principality, with the approximate borders marked in black and Ibn Jubayr’s route in green.

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Ibn Jubayr’s travels in the Artuqids principality

Abu al-Hasan Muhammad ibn Ahmad ibn Jubayr (أبو الحسين محمد بن أحمد بن جبير) was born in 1145 in Valencia, died in 1217 in Alexandria, Egypt. He is known for a book documenting his pilgrimage to Mecca that began in 1183 and ended with his return to Granada in 1185. He wrote a vivid account of this journey in his book “The Travels of Ibn Jubayr (رحلة ابن جبير).” In 580 AH or 1184 CE, he arrived at Nasibin, a town in Upper Mesopotamia, now called Nusaybin in modern Turkey. This is an ancient city mentioned as early as the Assyrian period. In the 12th century, it changed hands many times and was briefly conquered by Ilghazi ibn Artuq (إيلغازي بن أرتق), who ruled Mardin from 1107 to 1122. Ibn Jubayr only passed through the southern outskirts of the principality a few years after al-Jazari began his service at the royal court. It is quite possible that al-Jazari’s monumental works had not yet been completed or that ibn Jubayr did not hear about them. One can still be impressed by Nasibin’s poetic description.

” Renowned for its age and its past, outwardly fresh but decrepit within, beautiful to look upon and of medium size, it stands in a verdant plain which stretches before and behind it is as far as the eye can reach. In this plain, Allah has made to run streams of water that irrigate it and flow in all its parts. The city is begirt with gardens, thick with trees bearing ripe fruits, and round it there bends, like a bracelet, a river with its banks beset with the gardens that cover it with their ample shade. God’s mercy upon Abu Nuwas al-Hassan ibn Hani (أبو نواس –The Father of Curls. The court poet of Caliph Harun al-Rashid, considered by many to be one of the greatest Arab poets of all time) said:

“Nasibin was pleased with me one day

And I was pleased with it. Oh, that my lot in this world were Nasibin.”

Ibn Jubayr continues to describe the city and the stream that enters the town, passes through the streets, and reaches the mosque, where it flows into two basins: one in the center of the mosque and the other near the eastern gate, which in turn reaches two fountains. This description is particularly interesting because al-Jazari describes in his book designs for six fountains that change their shape. All of al-Jazari’s fountains have a time-based control system. Today, it is trivial to control a fountain using an electronic control system. Still, in the 12th century, it was a significant engineering challenge, and al-Jazari proposed a variety of elegant solutions. A water source, such as the stream that Ibn Jubayr describes, and a water collection basin and a fountain are the components from which al-Jazari built his elaborate fountains, and the text demonstrates their availability.

The fountain with two tipping buckets, Topkapi manuscript, 1206

The fountain with two tipping buckets, Topkapi manuscript, 1206

In the following paragraph, Ibn Jubayr speaks of the rulers of the Nasibin Mu’in al-Din (معين الدين), the brother of Mu’izz al-Din (معز الدين), the ruler of Mosul. The rulers of Mosul in the 12th century were from the Zangid dynasty (الدولة الزنکية). Like the Artuqids, they are a Turkoman dynasty from the Oghuz tribes (ٱغُز) that ruled parts of the Middle East, including Mesopotamia, with varying degrees of independence from the Seljuk Empire.

The 1180s were politically complicated by Saladin’s pressure on local rulers in Greater Syria and Mesopotamia, including the capture of Aleppo in 1183, the capture of Diyarbakir in 1185, and a failed attempt to capture Mosul. The local princes ruled at his desire and, to a large extent, became his vassals. The Artuqids did not control Nasibin in 1184, which indicates the small size of the principality.

After meeting with a righteous sheikh named Abu al-Yaqzan (أبو اليقضان), Ibn Jubayr continues to Dunaysir (دنيصر). Today, medieval ruins remain 20 km southwest of Mardin on a tributary of the Khabur (خابور ) River. Dunaysar is not considered an important place in Islam and was never fortified. Its prosperity under the Artuqids is reflected in the remains of mosques and madrasahs. Here, too, Ibn Jubayr describes:

“This city lies in a wide plain and is surrounded by gardens of aromatic plants and green vegetables that are irrigated by means of water wheels (ساقية). It inclines to the character of the desert and has no walls. Filled with people, it has crowded markets and a wide range of commodities, being the emporium of the people of Syria, Dyar baker, Amid of the Rumi lands that give allegiance to the Emir Mas’ud. It has wide tillage and many conveniences.”

I don’t know why he mentions Diyarbakır (دير بكر) and Amid (آمد) separately. As far as I understand, Amid is the ancient name of Diyarbakır. It is interesting to note the water wheel (ساقية), the most efficient device for raising water, which was used until the introduction of motorized pumps. This is a mechanical device that utilizes a belt of buckets or jugs, powered by a vertical wheel connected to a horizontal wheel, which is driven by animals (oxen or donkeys). In Al-Jazari’s book, there are five water pumps or in Al-Jazari’s words: ” machines for raising water from pools, and from wells which are not deep, and from a running stream,” and one of them is a strange water wheel powered by a scoop wheel and a set of gear wheels but has a wooden fake cow. More on the fake cow riddle here.

Ibn Jubayr then tells us that the ruler of the city is Qutb al-Din (قتب الدين), who also rules Mardin (ماردين), Dari (داري), and Ras al-Ain (راس العين), and is a relative of the Zengid who ruled Mosul and Nasibin. He is referring to Qutb al-Din Ilghazi II (قطب الدين إيلغازي II), who ruled Mardin between the years 1176-1184 and even left us coins with his image:

Dirham Qutb al-Din Ilghazi II

Ibn Jubayr’s following paragraph is unusual and highly critical of Muslim rulers, except for Saladin. To understand it, one must know that names in Arabic have meanings: Saladin is Ṣalāḥ al-Dīn “a-Din” (the “L” is not pronounced) is “the religion” and “salah” means righteousness, good, decency, and honesty, so that the name of the Ayyubid general Saladin means “righteousness of the religion.” The meaning of the name “Qutb al-Din” is “the leader of religion,” and so on.

“These countries are subject to various rulers, after the fashion of the kings of the Arab nations in Spain. All these rulers embellish themselves with titles connected with religion(Din), and you will hear only awesome by-names and appellations that, for wise, are without profit. In this, the subject and the kings are the same, and the rich share this habit with the poor. Not one of them is known by a cognomen that fits him or is described by an epithet of which he is worthy. Not on save Ṣalāḥ al-Dīn, Lord of Syria, the Hejaz, and the Yemen, and famous for his virtue and justness”.

The second category of Al-Jazari’s book is devoted to:” On the construction of vessels and figures suitable for a drinking session. This chapter contains ten amusing inventions for drinking parties. For example, the automaton (mechanical doll) that drinks the king’s leaving. This is clear evidence that the Artuqid court in Diyar Bakr lived in peace with alcohol. There are plenty of references to Islam and its customs in the book, and at the same time, feasts full of play and amusement take place without any apology or concealment. Is it this duality that led to Ibn Jubayr’s outburst?

Ibn Jubayr continued south to Ras al-Ayn (رأس العين), still part of the Artuqid principality. I did not find any helpful information about the Artuqids there, but the description is so captivating that I have quoted it verbatim:

“This name (رأس العين=The head of the spring) is a most fitting designation, and in this place are the most excellent properties, may Allah be exalted has given vent to springs in its ground that pour forth fresh water. They divide into branches and flow in channels spread through the green meadows like stripes of silver stretching across a sheet of emerald, beset with trees and gardens that are disposed along their banks till the end of their cultivated valleys. Of these springs, two are the most copious, and one is situated higher than the other. The higher rises from the ground

between hard stones that form something like the hollow of a cave, large and capacious, in which the water rises until it becomes a vast cistern. The water then pours forth like one of the greatest rivers until it comes to the other spring. This second spring is one of the most wonderful of the creations of the great and glorious Allah. It rises from a hard stone at a depth of about four men’s statures below the ground, but the spring has opened out a cistern of that depth. Sometimes, a stout swimmer and a strong diver try to reach the bottom, but the water, so strong is the spring, repels him so that he does not reach half the depth and sometimes even less. This we saw with our own eyes. The water is clearer than pure water and sweeter than the spring of Salsabil [a spring in Paradise mentioned in the Quran] and leaves visible all that is in it. If a dinar is thrown into it on a dark night, it will not be hidden.”

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The clock of the doors and the Jewish question

Introduction

The clock of the doors is identical to the candle clock of the monkey in terms of its mechanism and does not warrant a separate post. Just like the old joke about “The Elephant and the Jewish Question,” the clock of the doors has nothing to do with Jews,  which are not mentioned in the “The Book of Knowledge of Ingenious Mechanical Devices” even once. The phrase “The Elephant and the Jewish Question” is usually used to describe an annoying person who tries to link any event, however universal, to the Jewish people and their problems. I hope I’m not one of them, and I don’t have any convincing reason why I went out to check what we know about the Jews of Diyarbakır and Anatolia in the 12th Century. However, what I discovered is strange and exciting, and maybe it will interest you too.

The Candle Clock of the Doors” The Book of Knowledge of Ingenious Mechanical Devices, “Topkapi manuscript, 1206

How does it work?

Al-Jazari himself wrote:

” It is like the previous model, from which nothing is omitted except the keeper and the monkey. The additions are as follows: around the perimeter of the candle holder, fourteen doors are erected, each with two leaves. When a constant hour has passed from the lighting of the wick, a ball falls from the falcon’s beak, and the door opposite the falcon opens, and a figure emerges, [made] according to the choice of the craftsman.”

Anyone interested in the mechanism can go back and read my explanation of the monkey clock or the candle clock of the scribe. I will briefly explain the opening of the doors.

During combustion, the candle will shorten, and the force exerted by the weight will push the candle mount upwards at a constant rate that depends on the rate of combustion. To the bottom of the weight is attached another wire that runs over the pulley on which the bracket sits with 14 doors. These rotate as the candle burns. When the ball falls, it pushes the figure who opens a door and represents the time that has passed. This process repeats itself every hour.

The Jews in the 12th Century

The history of the Jewish people in the 12th Century is not similar in Ashkenazi communities and Muslim Spain. In Europe, the 12th Century began with the Rhineland massacres, a series of mass murders of Jews perpetrated by mobs of the People’s Crusade in 1096. The communities on the Rhine (Speyer, Worms, and Mainz) were destroyed. In 1146, in a repeat of the events of 1096, Crusaders preparing for the Second Crusade attacked and massacred Jewish communities along the Rhine. The 12th Century more or less ended with One of the worst Jews massacres of the Middle Ages, which took place in York in 1190. An angry mob trapped the city’s entire Jewish community inside the tower of York Castle. Many members of the community chose to commit suicide rather than be murdered or forcibly baptized by the attackers.

In Spain, on the other hand, Jewish people under Muslim rule experienced tolerance and integration. Some historians refer to this period as the “Golden Age” for the Jews, as more opportunities became available to them. That lasted from the days of the Caliphate of Cordoba to the small independent Muslim principalities and kingdoms of the Iberian Peninsula known as “taifas” and the process of the reconquest of Spain by the Christians. Social integration allowed Jews to advance significantly in new fields, philosophy and science. Some of them wrote poetry, primarily Hebrew poetry. They wrote about everything: poems about Zion and the people of Israel, but also poems about wine and women. I don’t think there’s a connection between the cultural flourishing in Diyarbakır and the Jewish flourishing in Muslim Spain, but it’s still intriguing. The Golden Age began in the 9th Century and ended in the 13th Century, but some of the more familiar figures were almost parallel to al-Jazari. For example, Maimonides was born in Cordoba in 1138, two years after al-Jazari, and died in Cairo in 1204, two years before him. Maimonides is a true polymath: one of the most prolific and influential Torah scholars of all generations, as well as a prominent philosopher of the Middle Ages, a scientist, and a physician. In his thirst for wisdom, he formed a study group and a friendship with Jabir ibn Aflah (a Muslim scholar) ‘s son, and they studied mathematics, medicine, and philosophy together. This must sound strange to those who live in Israel today and are familiar with the ultra-Orthodox opposition to secular studies. The “Kuzari” book, ” Book of Refutation and Proof on Behalf of the Despised Religion,” which I still managed to study in high school, was written by Rabbi Yehuda Halevi in this Century, and I must mention Rabbi Abraham Ibn Ezra, a 12-century poet, linguist, biblical commentator, and philosopher. He also worked in mathematics and astronomy. One of the lunar craters is named after him. Ibn Ezra’s most important mathematical work is in Hebrew: “The Book of the Unit,” which deals extensively with the decimal system and how it is used, thus preceding Fibonacci, the main contributor to the spread of this method in the Western world.

Did al-Jazari know the books they wrote or even heard about them? It is impossible to know, but the likelihood is extremely low.

Jews in Diyarbakır

In 1518, the Ottoman government conducted a census. There were 28 Jewish families and three single men in Diyarbakır. These are the first definitive data we have. After that, a continuous Jewish presence peaked in 1905, but apparently, the presence of Jews in Anatolia predates the Muslim conquest. According to traditions held by the Jews of Kurdistan, the Jews arrived in Kurdistan as early as the Salomon’s Temple period and are descendants of the Ten Tribes. As written in the book of  Kings:

” In the ninth year of Hoshea, the king of Assyria took Samaria, and carried Israel away unto Assyria, and placed them in Halah, and in Habor, on the river of Gozan, and in the cities of the Medes.”

Although we do not have a complete geographical identification, the name “Habur” has been preserved to this day as one of the Tigris tributaries located near the city of Zaxo (Arabic: زاخو), about 300 km from Diyarbakir. Later exiles to Babylon by Nebuchadnezzar, King of Babylon from the Kingdom of Judah, joined them. So it is very likely that there were Jews in Diyarbakir in al-Jazari’s day.

A Jewish delegation meeting with an Ottoman official

The Strange Story of David Alroy

Alroy was born a year before al-Jazari in Amadiya, Kurdistan. At first, I was confused because the historical name of Diyarbakır is Amida, but these are two different cities. Amadiya is located in northern Iraq, about 400 km southeast of Diyarbakir. David Alroy studied rabbinical literature with Hasdai, the exilarch, the leader of the Jewish community in Persian Mesopotamia, and Ali Gaon, the head of the Sanhedrin,  an assembly of elders appointed to sit as a tribunal in Baghdad. There is a claim that he was also well-versed in all the Books of Magic and sorcerers. I’m not sure what books are included, but it’s a bit like Chekhov’s gun, which appears in the first act, firing in the third. I have already mentioned Benjamin of Tudela, and not for the better. He wrote:

” David Alroy took upon him to rebel against the King of Persia [in 1163] ; for which purpose he gathered together all the Jews on the Mountains of Haphton, and from other Nations, to go to lay Siege to Jerusalem A great Part therefore of the Jews had Faith in; him, calling, him their Messiah. As soon as the King of Persia heard of this Matter, he commanded him to be brought before him. The King asked him: “Are thou the King of the Jews?” He answered and said, “I am,” The King then called to his Guards, and commanded him immediately to be apprehended, and led away to prison in the City of Dabastan. Three Days after this, as the King was sitting together with his Princes and Chief Minitiers, deliberating about the Jew Rebellion, behold David, having made his Escape from prison and approached and stood before him. The King looked at him and enquired, “Who brought thee hither?” He answered: “My own wisdom, and my own Subtilty because I fear neither thee nor any of thy Servants.” At which the King cried out: “Seize him!” But his servants said: “We see him not, but only hear the sound of his voice.”

Alroy then crosses the river on his handkerchief, and the King’s servants are unable to catch him in their boats. The King threatened to kill all the Jews in his kingdom. The frightened Jewish community threatened Alroy with a total exclusion from the Jewish community (“HEREM”). “In the end, David Alroy was killed in his bed while sleeping.

The story has legendary elements (seeing and not being seen, walking on water) absent in the description of Alroy’s contemporary, Al-Samawʾal ibn Yaḥyā al-Maghribi, who converted to Islam. To me, comparing the stories is less important than the passage describing the Baghdad Jews’ yearning for redemption:

“In this letter [a letter that two men forged in the name of David Alroy], they announce to the Jews of Baghdad the coming of the redemption they have been waiting for generations, in which they determine the night when they will all fly to Jerusalem, the holy city. Although the Jews of Baghdad were proud of their wisdom and strength of mind, they nevertheless tended to believe in this thing. Their wives brought all their possessions and jewelry to these two men so that they could divide all the property as they saw fit. In this way, the Jews wasted all their possessions. They wore green clothes and gathered that night on the rooftops of the houses, eagerly awaiting the moment when they would fly on the angels’ wings straight to Jerusalem. The women raised their voices in tears because they feared that they themselves would fly first before their children or the babies they were breastfeeding, and then these babies would suffer hunger.”

It is pretty clear that the Crusades and the instability in Palestine and nearby countries resonated strongly with some Eastern Jews, who saw them as precursors of redemption. The fantastic picture of the preparations for the flight and the heartbreak of the morning after also appear in other sources. Was all this commotion the talk of the day in Diyarbakir? This time not in distant Cordoba but in neighboring Amadiya,? We don’t know; even if it did, it must have been a minor event in al-Jazari’s world.

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The pump and the Crankshaft

Introduction

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

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

Donald Rutledge Hill (1922-1994)

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

How does it work?

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

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

Combined drawing, al-Jazari, and Hill

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

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

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

Crankshaft

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

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

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

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

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

roman crank

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

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

330px-Steam_engine_in_action

Steam Engine, Wikipedia