Proceedings 5 November 1987. Lecture Room '90-High' University College, Oxford
"Animal-powered Machinery in the Medieval Period" - a paper illustrated with slides, given by Mr. Kenneth Major FSA, a founder member of the SHMTS.
Welcoming the speaker, the President alluded to his numerous publications in the field of his talk and to his work in the area of industrial archaeology in general.
———————
The lecturer began with a definition of the field he intended to cover in his talk. Animal-powered machines were those machines in which the effort of animals, or indeed men, was translated into rotary motion and power. He would not be dealing with vehicles, namely machines in which the tractive effort of animals was used to move between two places.
Animal-power machines to be described in this paper would fall into two principal categories: [a] that in which the machine rotated in a vertical plane [b] that in which it rotated in a horizontal plane. There was also a third minor category, that in which the motion was in an oblique plane. There would be slide illustrations of all three categories during the course of the lecture.
The vertical machines were essentially tread-wheels of one form or another. In these, the animal, or in the period under consideration more particularly a man, walked inside or outside the rim of a large wheel and by this walking, moved the wheel away from under the animal, thereby imparting rotation to the shaft on which it was mounted. Examples were still to be seen used in irrigation systems in third world countries.
The horizontal machines were driven by animals, and in this form man was rarely the power source. The animal moved under the machine and walking round a central shaft thus imparted motion to the machine. In the medieval period the animal was usually harnessed below the elements of the machine. 'Low level' machines, in which the animal was harnessed at a higher level than the machine, were mostly the product of the Industrial Revolution and products of cast-iron technology.
The oblique machines fell into two sub-types. In the first, called the oblique tread-wheel, a circular plate was mounted on a shaft which was held at an angle. The animal was tethered above the plate and its walking motion caused the plate to fall away under its feet thus turning the shaft. In the second, the oblique treadmill or paddle engine, the animal was tethered on top of a moving belt set at an angle and as it walked so the belt moved away below its feet, the motion of the belt turned pulleys or machinery. The lecturer showed a slide of a historic instance of the type still to be seen in Hungary.
The tread-wheel is perhaps the best known of all the medieval animal-powered machines and there were some good surviving examples of this type. Such survivals existed in the form of permanently mounted builders' hoists in large churches, or in big houses to raise drinking water from deep wells. The builders' hoists were also extensively illustrated in medieval documents, for example the Bible of King Wenceslaus IV, 1389-1400 (Nat. Lib. Vienna) or the Litomerice Bible of 1411. It was a small step from the builder's crane to the dockside crane of which many examples exist on river or sea wharves. The first of two surviving such cranes at Trier dated from 1413, and the Andernach crane of 1534 replaced an earlier boat-mounted model. As with builders' cranes, the dock cranes also appeared in many townscapes engraved in the 16th century, though clearly depicting long established installations, such as those pictures by Sebastian Minster. The speaker showed a slide of a dockside crane at L}neburg in north West Germany which was installed in the 1340s and still working in the 1830s when it was used to off-load a Stephenson locomotive destined for the Braunschweig railway.
Water-raising tread-wheels still existed in England, largely on the chalk downs. These were epitomized by the well-known examples at Carisbrooke Castle and at Greys Court near Henley. The speaker observed that he had recorded some 30 examples and in each case the proprietor believed that apart from his there was just one other known example in the country, the one at Carisbrooke.
There was medieval documentation for other uses for tread-wheels and famous example of their use in mining were to be seen in Agricola's De re metallica published in Basel in 1556 though depicting practise of the 15th century and possibly earlier.
Like the vertical machines, horizontal types did exist in Roman times. The horizontal direct-drive machines, in which the machine rotated at the exact speed of the animal, could be seen in the Roman examples of the 'hour-glass' corn mill or the oil-crushing edge-runner mill. It was not known how long the 'hour-glass' mill existed in manufacture, but the edge-runner mill existed in many forms into the medieval period and even beyond. Examples could be seen used on mining sites, in the De re metallica of Agricola and the Theatrum Machinarum Novum published by Bl?ckler in Nuremberg in 1662.
In the speaker's view, De re metallica was an assemblage of known methods and examples whereas B?ckler was a mixture of inventions which may never have been built and of workable machines. Later textbooks such as Natrus, Polly and Vuurens' Groot Vollkommen Moolenboek published in 1734 in Amsterdam, give precise working drawings for the construction of the machines.
The direct-drive mine haulage machine, in which the animal winds a rope on to a drum mounted on the vertical shaft, was also well known in the mining districts of central Europe, and again, whilst much later examples still exist, medieval illustrations can be seen in the Kutna Hora Privileges of 1525 or the panel painting of St Anne of 1513 in Roznava church in Slovakia.
The indirect-drive machine could have existed in parallel with the direct-drive machines. Indirect drive machines are ones in which the rotation of the animal is speeded up by the introduction of gears between the animal wheel and the machinery being driven; the horse-driven corn mill was an example of this. The cog and rung gears which are to be seen on the primitive water-raising machines of the Middle East and the Iberian peninsula could be used, and were used, in the generation of power for milling in many parts of England and in continental Europe. Examples of this were to be found in England from the late eighteenth century and there was no reason to believe that they did not exist in an earlier period. Again, documents such as Blckler and Faustus Verantius's Machinae Novae of 1616, showed many examples of the geared corn mill i.e. the indirect drive.
Builders' treadmill crane Wenceslaus IV Bible, 1389-1400
Horse-powered winding gear at pit-head; Kutna Hora gradual, late 15th cent.
Geared horse well-hoist 15th-cent. MS, Geneva
The speaker concluded with the comment that the study of which his paper had been a digest should be regarded merely as the first stage in the assemblage of material on the topic. What was needed was that the study of documents and sites should proceed hand in hand in order to develop a much greater knowledge of all the machinery of the medieval period.
Dr Crombie thanked Mr Major for a comprehensive and interesting paper, with its numerous slides of historical and still existing sites. The meeting closed with questions from the floor and a discussion between the speaker and Mr.Michael Thomas, director of the Avoncroft Museum of Building, Bromsgrove of the horse-powered oblique wheel mill in Hungary.
Digest KM/GSH: Pics/GSH