Proceedings 23 April 1991 the Danson Room, Trinity College Oxford: following the society’s Annual General Meeting and having drunk the health of outgoing President Alistair Crombie.
TILTING AT SAWMILLS: AUSONIUS TO VILLARD an illustrated talk by Dr.Dennis Simms.
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The speaker began by recalling student days under Dr Crombie and two seminal remarks addressed by the then lecturer to his seminar: one, to follow Collingwood by asking sensible questions; the second, to buy a copy of Augustine to Galileo just about to be published, and thus aid an underpaid academic, to whit A. Crombie, eke out his frugal existence. A glance at his library shelves would show that the speaker had obeyed the second injunction; the paper about to be delivered might show to what extent he had observed the first.
Showing a picture of the Villard saw (ill. 1) he described it as the earliest drawing we had of a semi-automatic tool (alluding to the feed back mechanism which advanced the timber to the blade) but not the earliest known such saw, one being recorded at Evreux in 1204. In the last century Willis (whose descendant Faith Lyons was in fact among the members listening to Dr Simms) had pointed out that the machine had been sketched from memory rather than invented by Villard. The 1980s reconstruction at Honnecourt by Bechmann, de Vericourt and Jean Gimpel had revealed the sketches failings as a working drawing and required numerous imaginative modifications and adjustments. Villard, though, should not be harshly judged--men like Leonardo able to sketch e.g. a steam cannon (architronito) that worked as designed were rare.
The existence of the Villard sketch posed a number of questions.
[1] Was it an independent invention of the European Middle Ages?
[2] What water-powered mills were known to antiquity?
[3] Were they used only for the grinding of grain and olives?
[4] What sort of saws did antiquity have?
[5] What if any was the relation between medieval technology and that of the antique world, Byzantium and or the Arab world?
It also touched the main question for this talk--How might the water driven stone cutting sawmill mentioned by Ausonius in his poem Mosella actually have worked? The poem (AD 370-71) described a journey by the poet (a tutor of the future emperor Gratian) along the Mosel and its tributaries, probably en route to Trier, northern capital of the Roman Empire. The relevant passage translates: renowned is Celbis (the Kyll) for glorious fish and that other (the Ruwar), as he turns his mill-stones in furious revolutions and drives the shrieking saws through smooth blocks of marble hears from either bank a ceaseless din.
In his Medieval Technology and Social Chanqe the late Lynn White Jr. rejected the passage both on literary and technical grounds.
First he questioned the very authenticity of the poem though he was to accept Dr Simms' refutation of his arguments on this. On technical grounds White argued among other things: [a] that the saw needed to cut marble has a smooth blade used with an abrasive, would have had to be horizontal and would have involved mechanisms for the conversion of motion more complex than was possible at the time of Ausonius: [b] there was no marble near the Ruwar which he called 'an insignificant stream'; [c] the only stone in the area was in fact roofing slate which he claimed broke easily so could not be sawn [d] the design of such a saw as he supposed was unprecedented and would have required an isolated genius of the first order.
To refute these technical arguments Dr Simms 'said that [a] although the poem uses the word 'marmor' this was not conclusive evidence about the type of stone since the word had a general connotation at the time of Ausonius and could, for example, have signified limestone which was cut with vertical toothed saws and in any case the mechanisms to convert the motions would not have had to be so complex as White supposed. [b] The Ruwar was not an insignificant stream but capable of powering watermills (one was recorded there in the 7th century) and carrying barges which could have brought marble from distant quarries; [c] the slate in the area could be sawn and in fact was solid enough to be used in billiard tables and [d] the Mosel mill was not an isolated instance if one accepted one mentioned in Gregorius of Nyassa but unfairly rejected by White.
Dr Simms now turned to investigate possible mechanisms by which the saw could have worked and first addressed the question of converted motions. Since it appeared that the Roman world knew neither cam nor crank and connecting rod the possibility of a circular saw had to be considered. Ausonius certainly seemed to say that water wheels drove the saw blade(s) but his use of the word 'trahere', i.e. 'to draw', hardly suggested circular saws. Did the wheel indeed operate a crank mechanism or equivalent? Lacking contemporary technical texts we must leave the question unresolved.
Pace Ausonius and his 'trahere' the circular saw could have been known, Roman watermills had gear wheels and a circular saw could have been imaginatively extrapolated from the idea of an extremely narrow gear wheel with extra sharp teeth. Whether Roman metalworking was capable of producing a disc strong enough to saw marble with the aid of abrasive sand was another question. The speaker raised the possibility of a wooden wheel with wire wrapped round it. In his article 'Water-driven saws in Late Antiquity' (Technology and Culture 26, April 1985) he had suggested a wire band saw mechanism, though admitting the technical difficulties of wire drawing and power drive. The earliest record of the latter comes from the later Middle Ages but, suggested Dr Simms, an ancient inventor could have derived such a mechanism from an adaptation of the water driven chain of pots irrigation apparatus known as the noria.
(ill 2)
Why the sawmill came to be built is another question. It might be that the extensive building works at Trier coincided with the presence of an inventive genius and the whim of some powerful official. There were various reasons why, s0 far as is known, the design was not repeated in the western empire. Demand for large cut stone was in decline as walls to protect towns from barbarian sorties were largely completed. But major building works did continue in the eastern empire and there, we may now have archaeological evidence that a water-powered sawmill was built near Ephesos. It was also quite possible that the Mosel machine did not prove effective for long while the power generated might have been low. If the machine had worked stone from other parts of the empire, the breakdown in communications with the decline of imperial power would have stopped long distance transport, then again, as building activity shrank and buildings fell into decay they themselves could be plundered for dressed stone.
In response to a personal communication from Lynn White that the move to wood construction over the next 500 years would have prompted a demand .for machine sawing, Dr Simms had argued that sawmills required a level 0 f social and political stability which did not exist while if the Mosel mill were in fact .for marble the design would not have been adaptable to wood sawing. In fact even if the finds at Ephesos are con-firmed, we know that the sawmill disappeared in the eastern, Byzantine empire as in the west. Visiting Italy in the 1430s Cardinal Besarion, as Alex Keller had shown was astonished by western technical advances including sawmills, of which he had no knowledge. These no doubt were in the tradition of Villard's machine. This worked on the basis of converting circular to linear motion, as probably more efficient than any mechanism that could be supposed far the Mosel mill and was a design readily improved as gear-cutting and saw doctoring improved. If this was a truly independent invention the West was undoubtedly fortunate but the speaker paid tribute to the unknown genius who designed the mill at Trier. In conclusion he suggested that examination of lime stone and marble quarries or ancient buildings might reveal tell-tale saw marks and sand and investigation of waterways near ancient large building sites other sawmills.
Professor Crumbier thanked the speaker for a closely argued technical exposition (as also for having bought a copy of Augustine to Galileo) and led a lively and informed discussion from the floor. He then introduced the second speaker of the afternoon, Mr Philip Walker the digest of whose talk is given in Proceedings 24.
Summary: Geoffrey Hindley, Secretary SHMTS, based on material supplied by Dennis 8imms.
The author wonders whether anybody has followed up the suggestions he made in the last paragraph.
A visit to Ephesus revealed nothing about a water-driven saw alleged to have been discovered at the site by Austrian archeologists and enquiries of Vienna drew only a promise of a copy of the publication.
References
D.L.Simms, "Water-driven saws, Ausonius, and the Authenticity of the Mosella," Technology and Culture 24 (October 1983): 635-43.
D.L.Simms, "Water-driven Saws in Late Antiquity," Technology and Culture 26 (April 1985): 275-276
