Editorial note: This article needs to be read in conjunction with the book release review of the Arabic edition, see: https://muslimheritage.com/node/2068
The Mechanical Corpus of Al-Isfizārī in the Sciences of Weights and Ingenious Devices:
New Arabic Texts in Theoretical and Practical Mechanics
Mohammed Abattouy and Salim Al-Hassani
This essay is about our recent work on the critical edition and English translation of the Arabic texts composing the corpus of mechanics of Abū Ḥātim al-Muẓaffar al-Isfizārī. Al-Isfizari was a Muslim scientist who lived from the late fifth to the early sixth century after Hijra (the flight of Muhammad and his followers from Makkah to Medina to escape persecution 622 CE), corresponding to the late twelveth to the thirteenth centuries CE. This double publication deals with the field of mechanics, known in the Arabic scientific tradition as “the sciences of weights and ingenious devices” [ʿilmay al-athqāl wa-‘l-ḥiyal].
The work of al-Isfizārī in this field enhances the knowledge of historians and researchers of the Islamic Muslim heritage in science and technology, and specifically on the history of Arabic mechanics. It also confirms both the originality and innovative characteristics of the Arabic contribution to the field of machinery in terms of using mathematics and physics in both experimentation and theory. The work demonstrates how Muslim scientists’ ventures had substantially participated in transforming and developing scientific knowledge. In addition, this book elaborated its value from a history of technology and mechanical engineering perspective.
About the books
Up until recently, academic endeavour in medieval Muslim engineering was confined largely to few prominent figures, such as the Banū Mūsa (flourished ninth century CE), al-Jazarī (d. ca. 1206 CE), and Taqī al-Dīn ibn Maʿrūf (d. 1588), thanks mainly to the pioneering work of Eilhard Weidermann (d. 1928), Donald Routledge Hill (d. 1994) and Ahmad Yusuf al-Hassan (d. 2009). The edition of the corpus of mechanics of al-Isfizārī brings to light for the first time a new and large corpus of reworkings, commentaries, and recensions by a great, but previously obscure, scholar of mechanics from the generation preceding al-Khāzinī. One of his great achievements in mechanics was that he expanded the horizons of our knowledge of medieval mechanics, engineering, and technology as practiced by the scholars of the classical Islamic world. The publication of a critical edition of al-Isfazārī’s scholarship in theoretical and practical mechanics is, therefore, a highly significant publication in the field of mechanics and engineering history, and should prove to be a real treasure for the academic and the interested layman alike.
Figure 1 and 2: Cover of the Arabic 2013 (left) and English 2015 (right) books.
Al-Isfizārī and his manuscripts of mechanics
Al-Isfizārī flourished in Khorasan, an ancient region between the Iranian tableland and the Middle East, during the late eleventh to the early twelvth century CE, a period of time when the Seljuk Turks were the main political power in the region. He was a contemporary of ʿUmar al-Khayyam and Abd al-Raḥmān al-Khāzinī. A mathematician, astronomer, and author of texts in geometry, meteorology, measurements, and several works in mechanics. Al-Isfizārī was also a member of the team of scholars who worked in the observatory of the Seljuk Sultan Malikshāh in the city of Isfahan during the period 1074 – 1092 CE (467-485 AH).
Al-Isfazārī’s corpus of mechanics is composed of two sets of seven texts, which have been published by us in critical edition and complete English translation: A treatise entitled Irshād dhawī al-cirfān ilā ṣinācat al-qaffān [Guiding the possessors of learning in the art of the steelyard], a relatively long text on the mathematical theory of the steelyard balance with unequal arms.
The contents of this “Codex” have the form of a compendium in which al-Isfazārī collected his own abridgements and commentaries on the works of applied mechanics of his predecessors: Heron of Alexandria, Philon of Byzantium, the Banū Mūsa.
In addition to these three major components of the Codex, he added a text on pulleys by the Greek mathematician Apollonius, which had been mentioned by sources from Antiquity, yet had not been found until its discovery among the items of al-Isfizārī’s Codex. The inclusion of this text in the Codex has provided a unique opportunity to learn about some of the contents of Apollonius’ original text.
Finally, the Codex also includes a short fragment called Ṣūrat Ṣundūq al-Sāʿāt [Figure of the clock box] whose second paragraph describes a machine similar to the organ of Mūrisṭus, an obscure Greek author. The description of Mūrisṭus was described in some Arabic manuscripts and ascribed to that ancient Greek author.
In both the Irshād and the Codex, al-Isfizārī gathered together, edited, revised, and summarised the works of his predecessors, as well as added new results of his own. The list of authors and texts he touched upon is vast and highly impressive. They include: Pseudo-Aristotle, Pseudo-Euclid, Philon of Byzantium, Heron of Alexandria, Apollonius, Mūrisṭus, Thābit ibn Qurra, and the Banū Mūsā. This attempt to create what amounted to an encyclopaedia of the whole corpus of Greek and Arabic scholarship in the field of mechanics is unique in the literature of Arabic-language mechanics.
Figure 3: Inside view from the Appendix of manuscript samples (Arabic book, 2013)
Overview of contents
The first part of our work was devoted to reconstruct an extensive biography of al-Isfizārī, as well as a bibliography of his works, and analyses the historical and scientific context of his contribution within the tradition of mechanics in Muslim civilisation, and in the history of mechanics at large.
The second part is more technical and specialised, presenting and critically analysing al-Isfizārī’s corpus of mechanics. In order to present an accurate and rigorous critical edition of al-Isfazārī’s scholarship in this field, we utilised all known extant manuscripts of al-Isfizārī’s work, housed in libraries across the world, including: Manchester, Hyderabad, Tehran, Damascus, Saint Petersburg, and Philadelphia. The result attained after hard work was the reconstruction of the texts of seven treatises, of different lengths, making a total of about three hundred pages of Arabic text and diagrams. The critical edition is accompanied by a detailed critical apparatus, consisting of variant readings documented in footnotes, and various tools along with data are also presented in five large appendixes (approximately 130 pages). Finally, all the diagrams (approximately 250) of al-Isfazārī’s corpus of mechanics were reconstructed and redrawn in the edition, mainly in line-drawing format, but also many were reconstructed in 3-D. Such modern diagrams greatly aid in understanding the original texts and sketches.
Figure 4: Page 423 of the Arabic book presenting folio 17r of the Manchester manuscript presenting a part of Al-Isfizārī’s recension of Banū Mūsā’s Kitāb al-ḥiyal.
Significance of the Work
By reconstructing the life and works of Abū Ḥātim al-Muẓaffar al-Isfizārī and presenting the first complete critical addition of his scholarship in mechanics, the two editions in Arabic and English, Matn al-Muẓaffar al-Isfazārī fī cilmay al-aṯqāl wa’l-ḥiyal (2013) and “The Mechanical Corpus of Al-Isfizārī in the Sciences of Weights and Ingenious Devices: New Arabic Texts in Theoretical and Practical Mechanics” (2015) fill a gap in the study of mechanics in the classical Muslim civilisation, as well as in the history of mechanics at large. It brings to life the legacy of a long-neglected, but extremely important and original scientist. What is more, it renders his ambitious and unique attempt to create what amounted to an encyclopaedia of the whole corpus of Greek and Arabic scholarship in the field of mechanics until the early sixth century CE, into a readable, modern, critical edition and English.
Providing such a critical edition and English translation with an introduction and large appendixes, which was the product of years of painstaking work, is just the first step aiming to provide the texts with historical analysis. The second step should consist in the internal analysis of this scientific corpus. This analytic endeavour may be carried on by the the two authors who unearthed the original corpus or by other scholars in the field of Islamic studies.
Never published before, the corpus of mechanics left by al-Isfizārī includes a collection of texts in theoretical and practical mechanics, the two main fields of mechanics as practiced in ancient and medieval times. This corupus corresponds to the two designations organised the field of Arabic medieval mechanics which are extensively characterised in the two books: ʿilm al-aṯqāl [science of weights] and ʿilm al-ḥiyal [science of machines or ingenious devices]. The texts of al-Isfizārī in these specialties are seven in number. Two of them, one being al-Isfizārī’s original writing and the other al-Khāzinī’s edition of the same writing, are classified under the science of weights. The five other texts deal with machines and their functions; they belong to the field of practical mechanics. Here is the list of these seven texts:
1. Irṧād ḏawī al-ʿirfān ʾilā ṣināʿat al-qaffān [Guiding people of knowledge in the art of the steelyard]: a treatise dealing with the theory of the steelyard, the balance with unequal arms and the running counterpoise, known as al-qarasṭūn, al-qaffān, and al-qabbān. This text is extant in one incomplete copy.
2. The Irṧād has been published in a summarised version by al-Khāzinī in his famous encyclopaedia of mechanics Kitāb mīzān al-ḥikma [Book of the balance of wisdom][] under the title Fī marākiz al-aṯqāl wa-ṣanʿat al-qaffān li-‘l-Muẓaffar Al-Isfizārī [On centres of gravity and the art of the steelyard by […] al-Isfizārī]. Al-Khāzinī’s version contains two parts: an abridgement of the Irṧād, and a second part that preserves a missing section of the Irṧād about the description of the parts of the steelyard and its working procedure. The two parts complete each other to produce together a unique work on the steelyard, its properties, and functioning, which has no similar counterpart in the Arabic tradition of mechanics.
The texts pertaining to the ingenious devices [ḥiyal] are centred around the description of a great set of various machines and instruments. They are contained in a long manuscript without title extent in three copies of various lengths. This manuscript, to which hereinafter we refer as Majmūʿ fī al-ḥiyal [Codex of ingenius devices], contains three main texts plus two short ones. In these, al-Isfizārī summarised the works of his predecessors in the field of mechanics. In chronological order, these texts are:
3. Ḥikāyāt kitāb Fīlūn al-mījānīqī fī al-ḥiyal [Reproductions of machines in the book of Philon the mechanician]: Here al-Isfizārī summarized and reproduced most of the machines described by Philon of Byzantium (lived in Alexandria between 280 and 220 BCE). For that, he very probably used the Arabic translation made by an unknown translator of Philon’s Kitāb fī al-ḥiyal al-rūḥāniyya wa-majānīq al-māʿ [Book on spiritual and hydraulic machines], known in literature since early modern times as The Pneumatics.
4. Maʿānī kitāb Īrun al-mījānīqī fī rafʿ al-ʾaṧyāʾ al-ṯaqīla bi-‘l-quwwa ‘l-yasīra [The notions of the book of Heron the mechanician on raising heavy objects by small force]: Here al-Isfizārī summarised the main concepts and meanings of Heron’s (lived in the first century CE) well known and influential book “The Mechanics”. This book was translated into Arabic by Qusṭā ibn Lūqā in the ninth century in Baghdad under the title Rafʿ al-ʾaṧyāʾ al-ṯaqīla bi-‘l-quwwa ‘l-yasīra. The Arabic translation was edited twice and as it is the main source for Heron’s Mechanics after the loss of the Greek original, it is widely used by historians of mechanics and technology.
5. Ḥikāyāt ṣuwar kitāb al-ḥiyal li-Banī Mūsā [Reproductions of the figures of machines in the Book of Ingenious Devices by Banū Mūsā]: In this text al-Isfizārī summarised and reproduced the one hundred machines of the famous Kitāb al-ḥiyal ascribed to the three Banū Mūsā (lived in the first half of the ninth century in Baghdad). This famous book of practical mechanics, written mainly by Aḥmad ibn Mūsā, is one of the most important works of Arabic mechanics and fine technology. It was edited and translated into English recently by Donald Hill and was published by Springer Science & Business Media, 31 Dec 1978. Its contents were thoroughly studied and analysed by various scholars.
6. Kitāb Ablūniūs fī al-bakara [Book of Apollonius on the pulley]: It is a work of the renowned Greek mathematician Apollonius of Perga (lived around 262 to 190 BCE), the author of the Conica, the canonical book on conic sections which was well known in the Arabic scientific tradition. Apollonius’ work on the pulley was referred to in Greek historical literature, yet remained unknown until now. Its inclusion in al-Isfizārī’s Codex of Ḥiyal provides a unique opportunity to access its content at least in part. As it sheds light on a text completely unknown until now, the discovery of this text is one of the most significant of the present book.
7. A short fragment in three pages under the title Ṣūrat ṣunduq al-sāʿāt> shifted to the first appearance of this fragment; there the title is capitalised]. The second paragraph of this text contains a clear reference to the hydraulic organ, a type of pipe organ blown by air ascribed in Arabic manuscripts to Mūrisṭus, a Greek author. The text of the latter, describing a musical instrument that could be heard over a distance of sixty miles, was published since the early twentieth century and later translated into English.
Our extensive work on the components of al-Isfizārī’s corpus of mechanics, shows that this corpus represents a new and important addition to the documentary sources of Arabic mechanics.
Figure 5: Page 134 of the Arabic book presenting the diagrams redrawn from al-Isfizārī’s manuscript; the two diagrams present the reconstruction of two of Banū Mūsā’s machines.
The authors would like to thank Professor Siegfried Zielinski, Dr Judith Bihr and Claudia Voigtländer for their encouragement and assistance in the preparation of this article.
 This article is a reproduction of “Allah’s Automata: Artifacts of the Arabic-Islamic Renaissance (800-1200)” published by the ZKM | Karlsruhe, on occasion of the exhibition Allah’s Automata (October 31, 2015 till February 28, 2016), within the exhibition Exo-Evolution as part of the GLOBALE. https://www.youtube.com/watch?v=a7e31g9zPVA
 Professor of history and philosophy of science at Mohammed Vth University in Rabat, Morocco.
 Emeritus Professor of Mechanical Engineering at the University of Manchester and President of the Foundation of Science, Technology and Civilisation UK.
 Mohammed Abattouy and Salim Al-Hassani, Matn al-Muẓaffar al-Isfizārī fī ʿilmay al-aṯqāl wa-’l-ḥiyal. Taḥqīq naqdī wa-dirāsa tārīkhiya li-nuṣūṣ jadīda fī taqlīd al-mīkānīkā al-ʿarabiya, Al-Furqan Islamic Heritage Foundation, London, 2013; also published in English: The Corpus of Al-Isfizārī in the Sciences of Weights and Mechanical Devices: New Arabic Texts in Theoretical and Practical Mechanics. English Translation and Historical Commentaries, Al-Furqan Islamic Heritage Foundation, London, 2015.
 A collection of texts to which we refer by the generic title Majmūc fī al-ḥiyal or Codex of Texts on Machines (or “on mechanics”).
 Kitāb mīzān al-ḥikma [Book of the balance of wisdom] by al-Khāzinī is a large treatise on the physical principles that underlie the functioning of a sophisticated hydrostatic balance, as well as the construction and use of the instrument. Completed in 1121–22 CE, it describes a complex instrument of which the main application was to weigh precisely different substances and loads so as to discriminate accurately between pure and mixed metals as well as between real gems and fakes. The book is divided into eight parts and eighty chapters. It includes long quotations witnessing the classical sources on pure and applied mechanics that reached the Islamic lands (the Pseudo-Aristotelian treatise on mechanical problems, Euclid, Archimedes, Menelaus) as well as texts revealing the development of the discipline in the Islamic civilization (Thābit ibn Qurra, al-Isfizārī, MuIsfizārī Qurra on pure and a, al-Bīrūnī, Ibn al-Haybn , Abū Sahl al-Qūhī, Al-Khayyām). The book covers a wide range of topics related to statics, hydrostatics, and practical mechanics, besides reproducing abridged editions of several texts by or ascribed to Greek and Arabic authors. The book discusses the definition of heavy and light, the centre of gravity, the stable and unstable equilibrium, as well as the theory of the definition of specific gravities and even the application of the balance for levelling, calculating exchange rates of currencies, and measuring time. The book of al-Khāzinī was published by Dāʾirat al-maʿarif al-ʿuthmaniya, Hyderabad, 1940. It was edited recently: see Kitāb mīzān al-ited, édition critique, traduction et commentaires de Faiza Laridhi-Bancel, L’Académie Tunisienne des Sciences, des Lettres et des Arts Beit al-Hikma, Carthage, 2008. For a short bio-bibliographic outline on al-Khāzinī and his works, see: Mohammed Abattouy, “Al-Khāzinī,” in: The Biographical Encyclopaedia of Astronomers, edited by Thomas Hockey, Springer, Berlin, Heidelberg, New York, 2007, pp. 629–630; published online at: https://islamsci.mcgill.ca/RASI/BEA/Khazini_BEA.htm, accessed 07/27/2015.
 The term ṯiql in the expression markaz al-thiql or marakiz al-aṯqal is systematically translated by gravity, to conform with the common use widely spread in the historical literature. Elsewhere, in the English translation of al-Isfizārī’s texts, ṯiql is rendered by weight.
Reconstructed samples of al-Isfizārī’s machines in 3-D environment: