Ingenious techniques and process

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In Byzantium

There’s a misguided and deep-seated belief that nothing was invented in Byzantium. However, specialists agree that up until the twelfth century the Byzantine Empire was one of the most technologically advanced civilizations in the Mediterranean world. This was probably due to the knowledge the Empire inherited from antique science, which served as a constant source of inspiration. The Byzantine Empire subsequently lost some of its capacity for innovation, but remained a point of transit via which innovations from neighbouring countries could circulate: Byzantium facilitated the diffusion of silk and compasses in the West, and the introduction of water clocks and irrigation methods to the Arab world.

In the sixth century, Alexandria was the scientific capital of the Mediterranean world thanks to its library and educational role; antique science was the basis for all innovative thinking. Anthemius of Tralles was one of the great creators during this period: he conceived a device—based on Heron of Alexandria’s treatise Pneumatica (a description of mechanical devices that work on air, steam, or water pressure) and the use of steam—to simulate an earthquake in the home of his adversary, Zeno the Rhetor[1]; after studying commentaries by Eutocius of Ascalon on several Archimedean treatises (on the measurement of a circle, sphere, and cylinder), he collaborated with fellow architect Isidorus of Miletus on the construction of Hagia Sophia, a monumental project that enabled them to build the epoch’s largest dome; Anthemius also rediscovered Archimedes’s principle of catoptrics.

During this period, the textile industry evolved in Byzantium: Procopius[2] recounts that monks smuggled silkworms from China, which led to the development of sericulture in Syria, Asia Minor, and Greece; Constantinople became the centre of the silk industry in the Mediterranean world for a long time. Silks—which were offered to foreign kings as presents—played an important role in diplomacy. The colour purple, extracted from murex shells, also contributed to the prestige of the Byzantine textile industry: it was used to dye imperial clothes.

The seventh-century crisis led to an increase in Byzantine military innovation. The widespread use of the dromon (or chelandion)—long, light, and fast warships, propelled by oars or sails—and the adoption of triangular sails (known as Latin sails), favoured the pre-eminence of the Byzantine navy. Greek fire, invented by Callinicus in the 670s to defend Constantinople, was subsequently largely used against invaders who were terrorized by it: it was renowned throughout the medieval world. Called liquid fire, it was composed of naphtha, niter, sulphur, and bitumen. Its formula was kept such a closely guarded secret that its precise composition remains unknown to this day[3]. Greek fire was discharged from tubes and was used both in naval battles and on land during sieges. On the other hand, the invention of the stirrup, mentioned in the Strategikon (manual of war) authored by Emperor Maurice (582–602), led to the emergence of an effective cavalry. There were other contemporary technical innovations, such as the watermill and the shoeing of horses.

The ninth century was also a period rich in innovation, due in particular to the creativity of Leo the Mathematician. He may have invented the automata—based on Heron of Alexandria’s treatises—, which were operated by water and compressed air; they ornamented the reception room for foreign ambassadors and greatly impressed Liutprand: the levitating throne of Solomon, singing birds whose wings moved, and roaring lions[4]. Leo has certainly been credited with the invention of an optical telegraph—consisting of a system of beacons with two synchronized clocks at either end—stretching across Asia Minor from Tarsus to Constantinople, which gave advanced warning of Arab raids. In the field of medicine, it became possible to remove kidney stones without making an incision; doctors also succeeded in separating two Siamese twins whose stomachs were joined.

From the tenth century, Byzantine creativity began to wane, but the Empire remained open to foreign technologies: the Byzantines thus adopted Arab and Latin inventions, such as the crossbow.

However, it’s important to put this technological blockage in the Byzantine Empire in perspective. Indeed, two examples show that it’s advisable to remain prudent: the plough and scythe weren’t used in Byzantine agriculture—even though they were used in western Europe to meet the demands brought about by economic and demographic growth—but it’s important to understand that the predominantly uneven, dry ground in the Empire was more suitable for the swing plough and the sickle. The Byzantine civilization had a particularly outstanding capacity for adaptation: in addition to their success in preserving and transmitting the antique heritage, the Byzantines were also able to adopt inventions from other cultures.  Finally, it is certainly the case that the centuries rich in innovation coincided with the most glorious periods in the Empire’s history, and that the less creative periods tended to correspond with periods of political and economic crisis.

M.-H. C.

In Islam

Hydraulics: the Culture of Water

From the first centuries of Islam, the management of water and the need to compensate for a deficiency in rainfall were a primary concern for Islamic cities and rural areas. This need for mastering water and the effort involved drew from from a long tradition in hydraulic science dating back to antiquity, present in the Fertile Croissant, Iran and the Egyptian countryside. 

The adoption of hydraulic techniques for providing cities with water went hand in hand with the effort to maintain pre-existing ancient pipelines. Arab geographers were in awe over these sophisticated ancient constructions. Al-Idrîsî (twelfth c.), for instance, expressed his full admiration for the ancient Roman aqueduct of Toledo. Ibn Khladûn compared the Roman aqueducts in Carthage and Cherchell to the pyramids of Egypt. Other inspired adaptations of Roman hydraulic structures could be seen in Seville, in Jaén and Huelva. In Alep, the canalisation network that served most of the surrounding areas in the thirteenth century was in reality a copy of a pre-existing pipeline that had been built in antiquity. In Tunis, and in order to provide a solution for the great shortage of rainfall the city experienced in the thirteenth century, the Hafsids had to restore a large part of the Roman aqueducts of the region.  

With the expansion of Islam came a significant increase in plans for building large- scale hydraulic systems based on small hydraulic blueprints. This spreading of technical know-how led to a greater understanding of the methods for detecting underground water supplies and of how to bring it to the surface, as well as a generalised effort to collect rain water and to increase the volume of such reservoirs. 

The qanats (underground water galleries) thus spread from Central Asia to the southern Mediterranean and to the Arabian peninsular, to the Muslim West and Sicily, a term that had many different appellations (Karez, Khettara, foggara…). According to J. Olivier Asin, Madrid was provided with a network of qanats during the dynasty of Mohammad 1 (tenth c.), with galleries measuring from 7 to 10 km in length.

The geographer al-Idrisi has taught us that the feat was carried out by an Andalusian engineer commissioned by the Almoravid sovereign Alî b. Yûsuf (1106-1143) who introduced the technology to Marrakech in order to resolve the problem of water in the Almoravid capital.

Considering the affordable cost and certain profit of such technology, it began to spread rapidly throughout the Muslim world. The typical Muslim peasant in the Middle Ages used other irrigation systems such as the shâdûf or sâ?ia, also known as the sâniya. In cities, construction of elevating wheels rendered the river waters accessible, such as the construction in Alep, Hama and those of Albolafia in Córdoba, which were financed and put into practice by the Almoravid emir Ibn Tâshafîn,  their diameters reaching up to 15m, including the large noria in Toledo, installed between the al-Cantara bridge and the Roman aqueduct. 

These machines, which were very often based on sketchy technical notions, were carried out thanks to a practical savoir-faire and knowledge of the terrain, thus profoundly altering the agrarian landscape during that epoch. In current Spanish irrigation terminology the Arabic origin of many of the words (such as: alberca; azud; algibe; noria; aceña, etc.) testifies to the great influence of this culture of water, present throughout the Mediterranean.   

As hydraulic systems and agricultural practices evolved, new crops were introduced of tropical or semi-tropical origin (rice, sorghum, sugar cane, cotton, aubergines, etc.).

Muslim mechanical engineering and machanics

The undertakings in mechanical engineering carried out by Muslim mechanics in the Middle Ages led to a number of important treaties. Beyond their work of appropriating and assimilating a considerable body of knowledge inherited from antiquity, they contributed to a number of technical improvements—the fruit of their labours. The Banû Mûsa brothers from Baghdad were the authors of the treaty (The Book of Ingenious Devices) composed around 850 and inspired in part by the ideas of Heron from Alexandria (125 AD) and Philon from Byzance (230 AD).

In the eleventh century, the Andalusian al-Murâdî invented automatons constructed by complex systems of segmental and epicyclical gears. But the only remaining Arabic manuscript, copied in Toledo and currently in preservation at the Biblioteca Medicea Laurenzia of Florence, is completely disfigured.  

It was not until al-Djazarî wrote his treaty, finished in 1206, that this art of mechanical engineering came to be improved even further. The document is deemed the most important of its kind in its study of machines from antiquity to the Renaissance. The book abounds with sketches of machines, such as, for the first time, a lifting machine that functions using a system of cranks. Al-Djazarî also conceived of the technology for a sucking and twisting pump, thus contributing significantly to the beginnings of mechanisation.

In reality, these inventions were catalysers in technical science or in the Arabian school of mechanical engineering. Correlatively to this profusion of treaties, instruments for calculating time and establishing the hours of prayer were very much in vogue and all the great city centres of the Muslim world had monumental clocks.

One of the first texts relating to the existence and first use of this type of instrument came to us from Einhard, one of Charlemagne’s biographers. Towards 807, the Caliph of Baghdad, Harûn al-Rashîd (786-809) bestowed gifts upon the French king in Aix-la-Chapelle, among which a hydraulic clock. It was, in Einhard’s words, “a golden clock in bronze, the construct of the most admirable art. A mechanism moved by water that marks the course of twelve hours, and at the very moment each hour ends, an equal number of little bronze balls fall on a bell below them making for a tinkling sound as they fall. There were also twelve cavaliers who, when the twelfth hour comes around, come out by twelve windows, closing them behind them, in the sudden burst of their entry, the windows that had so suddenly opened.”

Other realisations of this kind were recorded by the great chroniclers of the Muslim world. The Andalusian traveller, Ibn Djubayr, on a visit to Damascus from 1184-85 wrote a long description of the monumental clock on the Great Umayyad Mosque. Thanks to specially adapted mechanisms, the clock could indicate not only the hours of the day but also the hours of night. 

The geographer, Yâkût al-Hamawî (m.1229) speaks of this type of clock in Malta during the reign of the emir Yahya, a period that inspired other constructions of this type and namely the one in Palermo which was installed in 1142 by Roger II. The archaeological remains attest to the presence of an inscription on the clock in three languages (Latin, Greek and Arabic)[5].

Of all these models cited in medieval documentation, only the clocks in Fez appear to have survived the ravages of time. The two clocks that survived go back to the fourteenth century—one on the Great Mosque, al-Karawiyyîn, and the other near the Medersa al-Bû’nâniyya.

T.M.