Islamic Civilization

Water  and Wind Mills

Hill, in an observation on wind and water power touches upon the usual dismissive attitude to Islamic accomplishment. He says:

‘We do now have a reasonably clear picture about the development of water based industries in medieval Europe from the 11^th century onwards, but until now very little has been published on the situation in Islam. Some historians (nearly all, Hill should have said), assuming from the lack of available information that the Muslims made only limited use of water power, have constructed theories to explain this apparent lack of interest as being due to factors inherent in Muslim society. These theories are, however, based upon a faulty premise, since it can be demonstrated that the Muslims were anything but indifferent to the benefits to be obtained from the exploitation of water power.’[1] 

These generalised Western assumptions are erroneous, and the following will show that the use of water and wind mills was not just widespread in Islam, but also that every single innovation related to them took place centuries ahead of Western Christendom. 

Water  Mills

Leading amongst Western historians in demeaning the role of water mills in the land of Islam is Lynn White Jr, who holds that:

‘The lands of medieval Islam were generally so arid that, even where there was enough water for agriculture, the flow of streams was too scanty or sporadic to operate many mills to grind grain.’[2]

Having stated this, Lynn White goes on to build his usual argument, why naturally powered mills developed in the Christian West. Of course, Lynn White is wrong, and on every single count.

There was a great deal of use of water to activate machinery in the Islamic world. This was done primarily through two varieties of water mills: the non geared horizontal mill, powered by a horizontal wheel with paddles (the ancestor of the turbine), connected directly to the bedstone by a shaft, and the vertical mill (either overshot or undershot), whose motive force is transmitted to the stone by a gearing mechanism.[3]

Hill describes the wheels that activate such mills:

-The vertical undershot wheel is a paddle installed on a vertical axle over a running stream, and whose power is derived nearly entirely from the velocity of the water.

-The overshot wheel, also vertical on a horizontal axle, with rims divided into bucket like compartments into which water discharges, usually from an artificial channel.

-The Horizontal wheel, which can be sub-divided into two types. The first has curved or slanted vanes fitted to a central wooden rotor, and is mounted at the bottom of a vertical shaft and water from an orifice fitted to the bottom of a water tower is directed on to the vanes, the flow being thus tangential. The second type is a vaned wheel fixed to the lower end of a vertical axle, and is installed inside a cylinder into which the water cascades from above, turning the wheel mainly by axial flow.[4]

Hill insists on the need to know about the origins of the horizontal wheels as they are the direct ancestor of modern day turbines.[5] He holds that the second type of horizontal wheel was unknown in Europe before the 16^th century, but appeared in the 9^th century treatise of the Banu Musa brothers.[6] This raises the interesting question, once more, of how did knowledge of such technology transfer between places. It also draws attention to the crucial element that will be raised recurrently in this chapter, that is the considerable number of technological innovations that appeared in the Islamic world centuries earlier than in the Christian West, completely contradicting the generalised assumptions found in Western history, which speak of innovations in Western Christendom, when these were already made centuries earlier. In relation to vertical mills, for instance, these were introduced by the Muslims in Spain, and they were used for the milling of grain and for industrial uses.[7] The vertical mill diffused northwards into Castile, with the name acena (from Arabic saniya) which always denotes verticality in medieval Castilian documentation.[8] Not only were acenas semantically differentiated from horizontal mills, but their geographical distribution followed a characteristic pattern, with acenas located on large rivers and horizontal mills on smaller streams, owing to the different hydraulic requirements of each.[9]

Another instance which highlights both Islamic advance on the Christian West, and on its predecessors, relates to the use of the overshot mill wheel, in which the water is conducted through a channel to the top of the wheel, which has bucket like compartments around its rim.[10] The overshot wheel works mainly by the weight of the water, whereas the Vitruvian one is operated by its force. In many conditions, the former is the more efficient of the two,[11] its use recommended by al-Muradi (11^th century).[12] The geographer al-Dimashqi (d. 1327) describes one such wheel in operation near Tabriz.[13] The advantages of the overshot wheel were well documented by Muslims. The 13^th century geographer, al-Qazwini (d. 1283), quotes an earlier lost passage from al-Udhri, that says that when water is scarce, vertical wheels could be converted from undershot to overshot wheels. The passage reads:

‘When the water which moves it is scarce they take a thick log of some ten palms in circumference by seven cubits long. They saw it into two halves and hollow out each half from one end up to half a cubit before reaching the other. Both pieces are joined and in the solid end they make a hole as wide as a donkey’s hoof. They erect it over the canal so that the end which has the hole rests on the wheels; the water exits forcefully through the hole in the log, strikes the teeth of the wheel, and the mill begins to turn.’[14]

The overshot wheel did not come into generalised use in the West until about the 14^th century.[15]  

Muslims mastered the use of water mills not just centuries ahead of the Christian West, and not just in isolated regions, as usually stated, but throughout the land of Islam, where they were used in great numbers. The 10^th century geographer, Al-Muqaddasi, for instance, speaks of the ‘wonderful mills on the water;' near Nishapur in Khurasan, where there were seventy of them on the river.[16] One description of the Kur River dam in central Asia, mentions ten water wheels in the vicinity driving mills.[17] Bukhara  was noted for the number of its mills driven by undershot wheels.[18] There were many corn mills in Tabaristan, too.[19] To the west, in Egypt , the town of Bilbays, on the eastern branch of the Nile in lower Egypt, was an important grain processing centre, the many mills there grinding corn for export to the Holy cities of the Hijaz. Al-Muqaddasi estimated that the annual output of grain and flour amount to 3,000 donkey loads (say 300 tons).[20] In North Africa , 400 mills (also including wind-mills) were seen in Fes  in the year 1184.[21] The Repartimento of Majorca, following its capture from the Muslims, documents 162 mills, and Miquel Barcelo estimates that just before the Christian conquest of 1229, there were around 197 mills in all.[22] There were also references to mills in places such as Jaen and Merida.[23] In 10^th century Palermo , then under Muslim rule, the banks of the river were lined with mills.[24] And the instances could be multiplied. Such was, one could say the Muslim obsession and expertise in water mills, as Hill points out, Islamic engineers would evaluate the number of mills a water way would activate on first sight.[25] In fact, medieval Muslims saw each water way not just in terms of its agricultural benefits, or poetical inspiration, but always looked at it from the perspective of how many mills it would generate. Thus, al-Muqaddasi looking at the Tigris at its source estimated that it would turn one mill,[26] and al-Istakhri looking at a fast flowing stream in the province of Kirman, estimated it would turn 20 mills.[27] 

Smith points out that just as in Europe, water power in the Islamic world was applied at first to raising water and grinding corn but was gradually extended to such works as sugar cane crushing, fulling and paper making.[28] In a treatise on mineralogy, written between 1041 and 1049, Al-Biruni  (d.ca 1050) gives the following description:

‘The gold may be combined with stone [i.e ore] as if it were cast with it, so that it needs pounding. And mills pulverise it, but pounding it by mashajin is more correct and refined treatment-it is even said that this increases its redness, which if true is strange and surprising. The mashajin are stones which are fixed to axles that are erected across running water for pounding, as is the case in Samarqand with the pounding of flax for paper.’[29]

The process in paper making, using water power, is explained by Derry, Williams and Hill. They tell us that raw materials for paper included straw and wood as well as linen and cotton, and the first task was to beat the material to a pulp and mix it with water to disperse the fibres.[30] This was expedited by the stamp mill, using a wheel and tappets to raise and drop pestles in mortars. The mill was at first turned by hand but later by water (or wind) power.[31] The mills used trip hammers operated by vertical undershot water wheels that pounded the raw material (linen, flax or hemp rags).[32]

Water  power was used in other manufacturing processes. Pacey observes that a new type of mill had been introduced in Iran  and Iraq  for processing sugar cane, as crushing the cane and then boiling the extract were the main operations necessary for obtaining crystalline sugar.[33] In many recent surveys in the Jordan Valley, the remains of 32 water powered sugar mills, dating from the Ayyubid-Mamluk period, have been recorded.[34] Applications of water wheels developed by the Muslims were also for fulling woollen cloth.[35] Ibn al-Balkhi, writing in 1107, calls a newly restored dam on the river Kur in Iran by the name of Band I-Qassar, meaning ‘fullers’ dam,’ an indication that its impounded water provided power for fulling mills.[36] Writing in the first half of the 12^th century, the historian Ibn al-Asakir mentions the use of water for sawing timber.[37]

One variation between Islam and the Christian West was the occasional use of dual purpose water wheels: norias used to drive the grinding stones of grist-mills.[38] The main difference, though, still remains in timing, Islamic water powered mills being centuries ahead of those of Western Christendom. Water  powered cane crushing mills are known to have existed in Basra  and other places in the 9^th century, and Al-Biruni   describes how such water powered mills worked, and how water power was used in driving trip hammers for paper mills in Samarkand  and in crushing gold ores.[39]

Generating hydro power in contrasting environments, using appropriate techniques, is further evidence of Islamic technological ingenuity. Hence, in an effort to improve the performance of horizontal and undershot water wheels, Islamic engineers were among the first to use river dams, generally not very large, to increase the velocity of flow and provide a measure of flow control.[40] Hydro power dams were especially numerous on rivers such as the Karun, Kur, Helmund and Oxus in the eastern caliphate and on the Guadalquivir in Spain.[41] In Khuzistan, the mills were placed in tunnels cut through the rocks at each side of the channel, which constituted an early example of hydro power dams.[42] A great deal of power was derived from the Guadalquivir river passing through Seville  and Cordova and linking them with the sea, by means of water wheels mounted on the banks, on floating barges and within or at least supplied from dams.[43] One of these dams still stands across the river at Cordova just below the Puente Romano, and until quite recently its three mill houses (al-Idrisi says that each contained four water wheels) were still functioning, but much altered from their original form.[44] In places, where the banks of the watercourse were high, as for instance, along the Euphrates, at Hama on the Orontes, at Amasia on the Yeshil Irmak, or at Toledo  in Spain, the current of the river itself was used to turn waterwheels, which produced energy for flour and paper mills.[45] Water  mills were also installed between the peers of bridges to take advantage of the increased rate of flow caused by the partial damming of the river.[46] Where the flow of water was not strong enough to work the mill, the stream was forced through a hollowed beam with narrow apertures at its end so that the water might come out in a jet and thus turn the mill wheel.[47] Tidal mills were also frequent, such as at Basra , where mills were operated by ebb tide. ‘The ebb tide is so useful for operating the mills because they are at the mouths of the rivers, and when the water comes out it turns them.’[48] Ship-mills were equally widely used to take advantage of faster currents in midstream and to avoid problems caused by fixed mills especially during the dry season.[49] Floating mills were mounted on floating platforms on the Spanish Ebro river at Saragoza, and on the Segura at Murcia.[50] Many 10^th century cities on the Euphrates and the Tigris had floating mills.[51] The people of Mosul erected water wheels on the Tigris and they also used to anchor floating mills in the river.[52] These mills were very large, made of teak and iron, and were moored to the banks by iron chains.[53] A 10^th century observer describes such mills:

‘The ship mills on the Tigris at Mosul have no equal anywhere, because they are in very fast current, moored to the bank by iron chains. Each has four stones, and each pair of stones grinds in the day and night 50 donkey loads. They are made of wood and iron-sometimes of teak. At Balad, not far from Mosul, there were a large number of these working to supply Iraq … There were a certain number of them on the Tigris at Haditha; the revenue was about 50,000 Dinars.’[54] 

In the year 1183, Ibn Jubayr  informs us that in Upper Mesopotamia, ship mills across the River Khabur, formed, as it were, a dam.[55] The large scale milling was necessary if we consider the demands from a city such as Baghdad , whose population was estimated at 1.5 million at the time.[56]

Once more, many such techniques followed in the Christian West centuries after Islam, the oldest illustration of a floating mill in the Christian West, for instance, is in a French manuscript of 1317, which shows the boats tied up between the piers of a bridge across the Seine in Paris, an arrangement which was in use as early as the 12^th century (during the reign of Louis VII, 1137-80).[57]

Wind Power

Just as with water power, mainstream Western historians, again led by Lynn White, claim, that windmills were never diffused in Islam.[58] Historical evidence, once more, shows the very opposite.

Wind-power was widely used in Islam to run mill stones and also to draw up water for irrigation.[59] This began as early as the reign of Caliph Omar  (634-44);[60] a pioneering role emphasised by Carra de Vaux.[61] Windmills were widespread east of the Islamic land, most particularly in ‘Sedjestan,' where the people, according to Al-Masu’di (d. c. 957), use wind to operate their mills and raise water from wells.[62] His contemporary, Al-Istakhri, too, noticed how the wind blows without interruption and operates mills erected everywhere.[63] Al-Qazwini (d.1283) refers to the grinding of corn by such windmills.[64] His contemporary, Al-Dimashqi (d. 1326-7), describes and makes sketches of such windmills.[65] He also gives explanatory notes.[66]

There are modern descriptions of the Islamic windmills. Khanikoff describes the windmill in Seistan in the following terms:

‘A millstone is attached to the end of a wooden cylinder, half a metre wide, and 3.5 to 4 metres high, standing vertically in a tower open on the north east side to catch the wind blowing from this direction. The cylinder has sails made of bundles of ush or palm leaves (which reminds of the modern European windmill), attached to the shaft of the axle. The wind, blowing into the tower, exerts strong pressure on the sails, so turning the shaft and millstone.'[67]

Forbes provides further outline on the operation of the mill,[68] whilst Wiedemann gives the sketch the 14^th century windmill,[69] clearly showing the mill above and the sails on the lower levels. Early Islamic windmills did include two storeys; in the upper storey were placed the millstones, and in the lower one, a wheel driven by the sails-six or twelve in number and covered with fabric-which turned the upper millstone.[70] Much more detailed description is given by Hill.[71] The windmills were erected on substructures built for the purpose, or on the tower of castles or on hilltops. The upper chamber was for the millstone, and the lower one for the sails. The walls of the lower chamber were pierced by four vents with the narrower end towards the interior, like the loopholes of a fortress so as to direct the wind on to the sails, and increase its speed.[72]   

With regard to the matter of impact, here, again, there are serious problems with mainstream Western historians. Bradford Blaine, for instance, says:

‘Windmills first appeared in Europe in the late twelfth century in Leicestershire in 1137… followed by rapid proliferation elsewhere. By the 1190s German crusaders were building windmills in Syria … What inspired their development is not certain.. The distinctive Western model appears to have been an independent invention, possibly suggested by the mechanical principles and efficient production associated with the familiar water mill in which the vertical wheel turned the horizontal drive shaft.’[73]

Hence, in his view Western Christendom impacting on Islam. This is wrong on many accounts. Never mind the fact that windmills appeared in the 7^th century in the Islamic world during the rule of Caliph Omar  (634-44), thus centuries before they appeared in the West. The focus here is on the point of the Germans carrying East this innovation. It makes no sense simply because White quotes the date for their spread in Europe: 1185 and after.[74] Now, the Germans were part of the first crusade (1095-6) and played a predominant role during the second crusade (1147-8) (Conrad III of Germany was one of the three main leaders of the crusade), so the question to ask is: how could they take something East, which was not even diffused in their own country at the time.

Wiet et al, despite their reluctance to accept Islamic influences on subsequent European techniques, did accept localised impact in the Iberian Peninsula (10^th century Catalonia), the Greek islands, and other Mediterranean  regions where water was too scarce for milling.[75] Hill notes the absence of windmills in Europe before the end of the 12^th century. To him, even if European mills were not inspired by Muslims in their design, the idea of using wind as a source of power came from the Muslim world.[76] Carra de Vaux points out that in Europe, the oldest text in relation to windmills is a French act of 1105 granting a religious community the right to establish one of these apparatuses, called molendinam ad ventum (moulin a vent in French: windmill in English).[77] Which coincides exactly with changes in other areas of European life: new construction techniques, methods of warfare, manner of dress etc, which coincide exactly with the return of the first crusaders from the East (the first crusade was launched in 1095), all manners of influence due to the crusades, which Prutz has expertly studied.[78]