Islamic Civilization

Muslim Engineers and Writers on Engineering

There is a very early treatise, Munro points out, on the making of water clocks, attributed to Archimedes, but in reality a very early Muslim work, possibly written toward the end of the 8^th century,[1] this is a further issue open for query. Less doubtful, though, is the identity of the earliest Muslim engineers known to us: the three brothers: Muhammad, Ahmed and al-Hassan, known as the Banu Musa brothers. They flourished at the Abbasid court in the 9^th century, and are the authors of about twenty works, only three of which have survived. There is a good entry on them in the Dictionary of Scientific Biography, even if the focus in it is on their mathematical works.[2] Their most renowned engineering work is the Kitab al-Hiyal (Book of Ingenious Devices) translated into English by Hill.[3] Written in Baghdad  about 850, this manuscript can be found in the Vatican (No 317) and also in Berlin/Gotha (Ahlward No 5562/Pertsch No 1349).[4] Kitab al-Hiyal includes the description of about a hundred devices, including trick vessels of various sorts, fountain lamps, and other apparatuses and gears including a gas mask for use in polluted wells. By far, one of the best works for any engineer to study such devices technically is a fairly recent publication by the IRCICA Centre at Istanbul, under the authorship of A. Bir.[5] This publication brings into focus many details on how the devices by the Banu Musa worked, their use, and their reconstruction. The Banu Musa’s work itself highlights a mastery of aerostatic and hydrostatic pressures, and the use of automatic control and switching systems, which, according to Hill, makes it a unique achievement, to be surpassed only in modern times[6] Wiedemann has focused on an apparatus used to gather pearls, which is formed by two half cylinders lowered to the deep sea, and which close upon each other when pulled up.[7] Klemm also gave his attention to this instrument.[8] This particular instance amongst many others, so anodyne it would seem, had many implications, however. First it discredits the opinions of mainstream historians of technology who hold the view that Islamic technology consisted only in water clocks and other toys for the amusement of courtiers. It highlights, instead, the practicality of Islamic technology; i.e for economic purposes; and also highlights Islamic precursors to modern tools and gears.

In the 10^th century, the construction of automata was probably a well established practice, since part of a scientific encyclopaedia is devoted to the subject.[9] This is The Keys to the Sciences (Mafatih al-Ulum), compiled in about 980 by Abu Abd Allah al-Khwarizmi (not the mathematician who lived a century and half earlier). The eighth treatise deals with ingenious devices (hyals), and lists a number of components and techniques with etymological  information that were used by makers of these machines.[10] This is a particularly useful work since al-Khwarizmi does not limit himself to definitions but also includes descriptions of manufacturing processes.[11]

From Spain came al-Muradi and al-Zarqali.  The only known manuscript of al-Muradi (11^th century) is so badly defaced that it is impossible to deduce from it precisely how any of the machines were constructed. Included in the treatise are five large automata machines that incorporated several significant features: each such device, for instance, was driven by a full size water wheel.[12] The text mentions both segmental and epicycle gears, and although the illustrations are in other respects quite incomprehensible, they clearly show gear trains incorporating both types of gearing, a century earlier than Al-Jazari’s (fl. 1206) water raising machines, which also incorporate segmental gears.[13] Sophisticated gears for transmitting high torque first appeared in Europe in the astronomical clock completed by the Italian Giovanni de'Dondi about 1365.[14] By some coincidence, and from the picture of one of al-Muradi's design, it comes out that his (Al-Muradi’s) manuscript was preserved in Florence at the Bibliotheca Laurenziana.[15] This very probable passage of knowledge from al-Muradi to De’Dondi, again, opens the issue of impact and transmission of Islamic technical knowledge.

At the same time as al-Muradi flourished so did Al-Zarqali of Toledo . Born to a family of artisans, he entered the services of Qadi Ibn Sa’id of Toledo as a maker of delicate instruments.  Around 1062, he constructed the water clocks of Toledo, which are described by al-Zuhri, and conveyed to us by Millas Vallicrosa.[16] A brief outline here highlights the ingenuity of the device. The clocks consisted of two basins, which filled with water or emptied according to the increasing or waning of the moon. At the moment when the new moon appeared on the horizon, water would begin to flow into the basins by means of subterranean pipes, so that at day-break there would be the fourth of a seventh part, and at the end of the day half a seventh part, of the water required to fill the basins. In this proportion the water would continue to flow until seven days and as many nights of the month had elapsed, by which time both basins would be half filled. The same process during the following seven days and nights would make the two basins quite full, at the same time that the moon was at its full.  However, on the fifteenth night of the month, when the moon began to wane, the basins would also begin to lose every day and night half a seventh part of their water, until by the twenty-first of the month they would be half empty, and when the moon reached her twenty-ninth night not a drop of water would remain in them.  It is worthy of remark that, should anyone go to any of the basins when they were not filled, and pour water into them with a view to quicken its filling, the basins would immediately absorb the additional water and retain no more than the just quantity; and, on the contrary, were anyone to try, when they were nearly filled, to extract any or the whole of their water, the moment the hands are raised, the basins would pour out sufficient water to fill the vacuum in an instant. The clocks were in use until 1133, when Ibn Zabara was given permission by Alfonso VII to see how they worked, but failed to reassemble them after dismantling them. As Al-Zarqali was dead by then, the details of his techniques were lost.[17]

A maker of instruments who will be fully considered further on in the chapter on physics, is Al-Khazini. Al-Khazini (d. 1123) in the eighth treatise of his Book of the Balance of Wisdom, describes the construction of two steelyard clepsydras, a light one for 1 hour operation and a large one for 24 hour operation.[18] What is worthy of attention about such works is al-Khazini’s awareness of the physical properties of fluids.[19] The clepsydras were designed to work either with water or sand. In the larger device a clepsydra is attached to the end of the short arm of the steelyard; a large weight and a small weight are suspended from the long, graduated arm.[20] As the water or sand discharges, the weights are moved along the arm to bring the machine into balance. The hours are read from the position of the large weight, the minutes form the position of the small one.[21] 

A better known Muslim engineer is Al-Jazari who spent his working life at the service of the Turkish  Ortoqid dynasty, which he served from about 1180 until some time between 1200 and 1220.[22] Al-Jazari narrates his experience:

‘I was in [Nasir ad-Din's] presence one day and had brought him something which he had ordered me to make. He looked at me and he looked at what I had made and thought about it, without my noticing. He guessed what I had been thinking about, and unveiled unerringly what I had concealed. He said, "You have made peerless devices, and through strength have brought them forth as works, so do not lose what you have wearied yourself with and have plainly constructed. I wish you to compose for me a book which assembles what you have created separately, and brings together a selection of individual items and pictures."[23]

Thus he wrote Al-Jami Bain Al-Ilm Wal-Amal Al-Nafi Fi Sinat'at Al-Hiyal (A Compendium on the Theory and Practice of the Mechanical Arts ), a treatise Sarton sees as ‘the climax of this line of Muslim achievement.’[24] However, it had to wait until Hill translated it in 1974, seven centuries and 68 years after it was completed by its author, to become more accessible.[25]

Winder notes that fifteen copies of the treatise are available, fourteen in Arabic, the earliest dating from 1206; and the latest, a Persian translation, dated from 1874.[26]

Al-Jazari's treatise includes water and irrigation devices, machines where robot girls place a drinking glass in the ruler's hand, mechanical flutes, decorative items such as a monumental door with one of the earliest descriptions of green-sand casting… etc.[27] Also included are monumental water clocks, with great spectacular visual effects: circles representing the zodiac rotating at constant speed; birds discharging pellets from their beaks to sound the hours; and doors opening at regular intervals to reveal musicians performing on their instruments.[28] Devices, which seem simple and even trivial, but which involve mechanisms of real ingenuity, and that were to impact dramatically on subsequent technology.[29]

Al-Jazari was clearly a master craftsman in his own right, who was capable of constructing large and small machines entirely with his hands.[30] This consisted of metalwork of all kinds, including casting in copper, brass and bronze, soldering and tinning, sheet metalwork and so on.[31] For his larger devices he would have needed the help of a labourer, and he may have trained apprentices, but otherwise he required no outside assistance.[32] In comparison, the Latin  treatise by Theophilus in the 1120s is the work of a master craftsman in paint, glassmaking and metalwork,[33] but with an engineering content which is much less than that of al-Jazari.[34]

Munro brings to attention the little known (or studied) Ridwan ibn Muhammad al-Sa'ati, who in 1203 wrote a lengthy treatise on the repair of a monumental water clock over the Jayrun Gate in Damascus . Ridwan's work is only available in one manuscript, dated from the 16^th century. A complete edition of the work has not been published yet.[35]

One of the very rare figures of Islamic science, who flourished after the 13^th century, is the 16^th century Syrian Taqi Eddin. In 1551, in Damascus , he completed al-Turuq al-saniyya fi alat al-ruhaniyya (The Sublime Methods of Spiritual Machines,). The manuscript is located in Dublin’s Chester Beatty Library (No 5252), but was edited by A.Y. Al-Hassan in 1976.[36] The manuscript is distinguished by its approach and style, both simple, intelligible and precise, and the many drawings, such as those of various methods of water elevation.[37] There are descriptions and illustrations of clocks, weighing machines, pumps, water turbines, and various other machines.[38] Al-Hassan stresses the significance of Taqi Eddin’s treatise in completing a lost link in the history of Islamic technology, besides describing several new machines which are not found in either the Banu Musa or Al-Jazari’s work.[39]