International Molinology
Journal of The International Molinological Society
No. 64, July 2002 / summary - résumé
Editorial
by Michael Harverson
Contributions to International Molinology are classified,
sometimes rather arbitrarily, as "Original Papers" or Communications". The
former are articles that demonstrate individual research or fieldwork that will add to the
common stock of knowledge of our subject. They generally result from someone’s
concentration on a molinological problem or former ‘black hole’ e.g. our almost
complete ignorance of the existence and history of windmills in Italy. Many years devoted
to exploring one’s chosen problem may have passed before one feels ready to write up
one’s insights to share them with others. So, in this issue we have the thoughts of
one member on the performance of windmill sails, a matter that has preoccupied him for
many years, both in his professional work on the application of modern wind engines for
electricity generation and in the part-time reconstruction of a smock mill, with a team of
fellow enthusiasts, which has finally reached the point where flour was ground at the mill
by windpower in 2001. A visit to Syria by an engineer specialising in waterpower led to
the chance ‘discovery’ of a dozen watermills sited on a steep hillside; his
descriptive and photographic record enables us to fill in a gap in our global coverage of
mills. (For most molinologists Syria has been represented only by the waterwheels of Hama,
magnificent though they are.) An archaeological excavation, also in the Near East, has
revealed the probable existence of a water-powered saw mill dating back to late Roman or
early Byzantine times in the modern state of Jordan, a stunning discovery that pushes back
by several centuries the first documented application of waterpower for this purpose. International
Molinology is privileged to be able to publish three "Original Papers" that
record these findings - the work of two TIMS members, British and German engineers, and of
a French archaeologist, in translation.
"Communications" are the sharing of items of news, experiences, appeals for information or responses to articles in earlier issues. So, here we have a selection of early postcards recording long-vanished windmills in Africa; news of a Danish project to promote waterpower in rural Tanzania; notes on mills encountered during a holiday on Tenerife; further comments on the tower ‘mill’ in the Czech Republic described in IM 62 and on the relation between millstone and sail or waterwheel speed discussed in IM 63.
It is always pleasing to be able to print opinions on material published in recent issues; they can contribute to a fresh interpretation of difficult or uncertain points. Please write to the editor when you disagree with something in an article or have extra information to offer, so that a dialogue can be established between the author and his readers in the columns of IM, advancing our common understanding of the subject that has absorbed his interest and efforts.
We are also beginning the search for another volunteer, someone with a sound competence in computing skills, to assist in the production of TIMS publications. These have been masterminded by Albert Bongers ever since Yolt Ijzerman introduced the IM format in 1994. He will be taking a well-earned rest after IM 65. He has guided Ian Scotter in his successful work on the lay-out of BM 16 and we can count on Ian’s commitment and expertise for the future. However, it would be wise not to depend on just one person in this key role and to recruit an assistant for the regular and time-consuming labour of scanning illustrations and preparing the lay-out. The editor will be delighted to hear from anyone interested in offering their services in 2003. Please enjoy the content of the new issue.
| Original Papers |
Traditional Windmill Sails: Design for Power
by David L. Pearce
Introduction: As a piece of engineering the
English corn-grinding windmill attained its greatest sophistication and success in the 19th
century, shortly before development came to an end with the widespread introduction of
large steam-powered flour mills. Much of the work of the old millwrights and regional
variations of millwrighting practice have already been discussed authoritatively in the
series of papers and books by Rex Wailes1. The present paper concerns practical
issues which were of great importance to the commercial windmiller and so to the
millwrights, but which have received little published attention. It was obviously of
fundamental importance to the miller that the sails should perform well, and allow him to
make a living. Bearing in mind the great variety of sail designs, what constituted an
effective design? A related question was how should the sails be matched to the load? For
a given set of millstones, or other load, this question essentially reduces to determining
the appropriate gear ratio between windshaft and load, so that in a reasonable breeze the
sails could run at a suitable speed for the adequate generation of power.
 |
Fig.2
|
Elsewhere in north-western Europe economic circumstances were different to those prevailing in England. For example in the Netherlands traditional windmills remained in widespread use, and sail designs continued to develop, through the first half of the 20th century (Fig.1). In Denmark from 1891 there was a most interesting development in the application of windmills to the generation of electricity, notably by Paul la Cour, a process partly encouraged by the lack of indigenous fossil fuel (Danish Wind Turbine Manufacturers Association, 2001). Early successful wind electricity plant tended to be new 'skeleton' smock mills with the Danish variant of patent sails, or sometimes converted corn mills (Fig.2).
In this paper I shall review practical evidence related to traditional sail design and performance, with particular reference to English practice. Other developments will be alluded to where appropriate, but for the most part this paper concentrates on traditional corn or pumping windmills and the matching of their sails to the mill's duty. I shall discuss the measurements and calculations which would be needed for fuller resolution of the issues raised.
(12 pages, 10 pictures, drawings and formulas)
Sixth-Century Waterpowered Sawmill
by Jacques Seigne
[We are grateful to the author and the publishers for permission
to reproduce this short note, translated here by Niall Roberts, which first appeared in
the French journal Archéologia No. 385, January 2002, pp.36-37.]
A re-examination of some remains excavated in Jordan in the 1930s strongly suggests the existence of a waterpowered sawmill 1500 years ago although, until now, it had been thought that such mills dated only from the Middle Ages. In his poem Mosella, written in the Fourth Century AD, Ausonius [a Gallo-Roman poet] says:
"…as to the other river, (the Erubrus, now known as the Ruwer, a tributary of the Mosel near Trier), it rapidly turns millstones that grind grain, and drives strident saws across blocks of smooth-sided marble, producing a continuous din audible on both banks of the river! "
These lines, apparently written in 367, have caused a lot of ink to flow. The use of waterpower for grain milling has been well substantiated from at least the beginning of the Christian Era, but such early use of waterpower for sawing wood or stone had, until now, been entirely unknown. No undisputed remains of a waterpowered sawmill have been found dating from Antiquity. In order to work, such an installation would have had to use a complicated mechanical device that could transform rotary motion into reciprocating linear motion, but the use of cams or cranks with connecting-rods has not hitherto been traced before the Middle Ages.
 |
Fig. 3 Drum abandoned while in process of being sawn. |
A discovery in the 1930s : In 1932 or 1933, during a programme of major excavations on the site of Jerash [ancient Gerasha, about 40km north of Amman in Jordan] under the direction of C H Kraeling, teams from the British School of Archaeology in Jerusalem and from Yale University uncovered the eastern end of the southern supporting vault (cryptoporticus) of the sanctuary of Artemis. One of the underground chambers opened up revealed the remains of a waterupowered installation of some kind, which has never been written up and published on account of the sudden discontinuance of excavation. Despite this, the surviving remains form a coherent whole that can be clearly interpreted (fig 1). We have been able to study this find through the kind permission of Dr Fawwaz Al-Khraysheh, Director-General of the Department of Antiquities of Jordan, and of Dr Roberto Parapetti, Director of the Italian Mission for the Study of the Sanctuary of Artemis.
In the courtyard of the sanctuary, a double channel fed two large cisterns that are currently in a very ruinous state. One cistern probably served as the header-pond for a waterwheel located three metres below in the subterranean chamber in question The side walls of the headrace and of the tailrace are still preserved, as are the positions for the bearings for the shaft of a vertical waterwheel (fig 2). During the excavations, the archaeologists found in the same chamber on either side of the tailrace two stone drums that had been partly sawn. These drums had been pushed against the walls of the chamber and they are still there today.
(3 pages, 4 pictures)
Tell Shihab Watermills (Syria)
by Valentin Schnitzer
Introduction: The literary sources dealing with early
watermills refer to the countries of the "fertile crescent", a cradle of ancient
cultures. Archaeological proof is given of hand operated rotary millstones, dating back to
1500 BC. Hand millstones were later improved and became widespread in the Roman Empire,
especially in the east.
Three years ago we started our search for early watermills in southern Syria, once a "granary of the Roman Empire". A local proverb saying "all ways lead to the mill" guided us to the unique concentration of watermills by the waterfall of Tell Shihab, where the water drops over a ridge of the northern slope of Wadi Chaled. This eastern side valley joins the Yarmuk valley that acts as Syria’s south-eastern frontier with Jordan. It is not far from the temporary border of the land occupied by Israel and gives the impression that this corner of the country looks remote and forgotten.
Until recent times watermills operated here, but they ceased to exist when water was primarily needed for irrigation and at the same time cheap diesel fuel and electrification led to the establishment of powerful mills in the settlements and towns.
The impressive remains of the mills still keep their secret of how they came into existence and were operated during the periods of flourishing cultures in that area. They challenge us to discover their origin and to preserve the place as evidence of a milling culture.
 |
Fig.6 Eastern cascade mills. Bottom: Arubah and chute. |
Location of the mills: In the fertile land north of
the valley all the water is now collected for the urgent need of irrigation and only a
little drainage water is left to feed the once picturesque waterfall - leaving no water at
all to operate water mills.
Based on the location of the mills, water was diverted into three branches for milling:
The western mill cascade whose mills ( T1, S5, S6) probably ceased to function some time ago when the milling focus was more in the centre and east.
The eastern cascades with the mills of T2, T3, T4 on the top slope below the ridge.
The waterfall in the centre fed only the mills S2 and S9, via an intermediate pond below the upper fall.
The main waterflow probably used to pass through the mill T4 and from there it would have been distributed to the eastern cascade with the mills S10, S11, S12 and part of the water feeding also the mills S8 and S9.
The tailwater of all the mills was then discharged into the stream at the bottom of the valley. From there three further channels diverted water to the mills in the valley, V13 and V14.
 Fig.5 Total view of Tell Shihab waterfall with watermills. |
(6 pages, 12 pictures)
The millstone industry of Houlbec-Cocherel (Eure)
by Owen Ward
Houlbec-Cocherel is one of hundreds of French
quarry areas which, although long since closed, enjoyed a regional reputation second only
to that of the better-known deposits of la Ferté-sous-Jouarre, some 30 kilometres to the
north-east of Paris.
The stone: The earliest information about the quarries found so far is in a paper presented by one M. Guettard, who used to address the Académie des Sciences on geological topics in the middle of the 18th century. The paper which concerns us, called simply 'sur la pierre meulière' (concerning stone for millstones) was delivered on the 19th of April 1758 [1]. Guettard began with a general history of types of stone used for making millstones from 1558 up until his own time, two hundred years later. By then a systematic method of describing various kinds of stone was being developed in France, and the expression pierre meulière was only just becoming identified by Guettard with 'a kind of flint similar to that used for flint-lock guns' [p.206] which might be non-porous or pitted with tiny holes, or pores. It could be reddish or yellowish in colour, varying to a whitish or even blueish tinge. When he came to identify the sources of pierre meulière he considered Houlbec-Cocherel and la Ferté-sous-Jouarre as the two main sites where it was to be found.
(3 pages, 1 map)
Tide Mills in Germany
by Walter Minchinton
Without suitable sites for tide mills, and
perhaps in the absence of a demand for extra sources of energy, there appear to have been
no tide mills along the German North Sea coast. However, the tide reached up the Elbe as
far as Hamburg, where the average tidal range was 2.80m., the height of the tide tending
to be lower in summer than winter, because in summer water was drawn off to irrigate the
crops. The tidal range at Hamburg had been increased by damming some of the branches of
the river and so tide mills could be established further inland than was the case
elsewhere in Europe. Three factors facilitated the construction of tide mills at Hamburg
in the sixteenth century. The canals in the city were improved and in particular the canal
between Oberhaus and Brooksbridge was deepened between 1536 and 1555. Better sluices
became available and were installed, in particular, opposite the Winsertor at Oberbaum. It
thus became possible to use the canals as reservoirs for tide mills. It is now suggested
that knowledge of the operation of tide mills was brought to Hamburg by travelling traders
who visited England, France and Holland, rather than by Dutch immigrants, a
long-established Hamburg legend.
 |
Fig. 1 The Graskeller Sluice c. 1660 |
(2 pages, 2 pictures and 1drawing)
| Communications |
Some Windmills in Afrika
by Chris Gibbings (3 pages)
The Millstone Quarries at Jonsdorf
by Gerald Bost (2 pages)
Download file: Jonsdorf.pdf (646KB)
Notes on the Mills of Tenerife (Canaries)
by Owen Ward
The Windmill Postcards of Spaander and Mol of Wormerveer (NL)
by Michael Yates
A Danish Mill in Tanzania
by Agnar Moltke
other subjects.....
| New Service: Download: Deutsche Zusammenfassung IM64d.pdf 105 KB |
Download: Résumé français IM64fr.pdf 145 KB |
ISSN 1024-4522
This summary of the 63rd Jounal of The International Molinological Society
has been prepared by Gerald Bost, Berlin - Sept. 2002.
The complete printed version can be ordered from TIMS Publication Officer:
Leo van der Drift
Groothertoginnelaan 174 b/c
NL-2517 EV Den Haag
The Netherlands
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Published: dinsdag, november 06, 2007 12:47:50
