Drawings after sketches of the author.
To the memory of Dr. P.G. van Tienhoven, founder and first chairman of 'De Hollandsche Molen'.
Windmills have always played a great part in the life of Holland and its inhabitants. While at first they served to grind corn, to remove excess water from the low-lying districts, and to saw timber, thus making the country fit for human habitation and adding to habitable area, they developed - especially in the seventeenth century - into a most important factor in the social structure of those days. It is with increasing interest that one learns about this.
Although it can be said that windmills which can be compared with the Dutch windmills are to be found in other European countries as well (England, Belgium, France, Denmark, Germany, Finland), it has to be observed that their number is relatively small there. It is only in Holland that so many windmills are present in so small an area. These windmills moreover are in very reasonable, many of them even in excellent, condition and a considerable number of them are working regularly. There are windmills of the most varied types: drainage mills, corn mills, and industrial mills for all sorts of purposes.
Windmills form an important element in the Dutch landscape with its wide horizons, its glittering waters and big clouds floating overhead; without them we can hardly imagine this landscape, which is unique in the world.
The following pages will show these windmills from the aesthetic, the historical, and the technical point of view. We hope they may help to deepen the fascination which windmills exert on the spectator, and to add to the pleasure of seeing them in their own natural surroundings.
'The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and wither it goeth: so is every one that is born of the Spirit.'
(St. John 3 : 8)
In the Dutch landscape the windmill is symbolic of the gravity of the Dutch character. Planted solidly on the earth, it is an incarnation of force; it seems as if it had grown up quite naturally from the soil, forming an integral part of the surroundings. It is in perfect harmony with the natural scenery around, built of native brick or thatched with reed as it is. Reed was ready to hand all around in this country intersected by waterways and it was used as a natural roof-covering by seventeenth-century Dutch architects just as it is today by architects of country houses. All the primitive structural parts of the windmill reveal simplicity, realism, and practical usefulness; its appearance testifies to its association with the primeval forces of nature: wind and water.
These two words, wind and water, have a very special fascination for the true-born Dutchman.
We realize how - many centuries ago - the inhabitants of these low-lying parts had to give all their attention to wind and water every hour of the day; how farmers and fisherman naturally chatted about the weather whenever they met, because their everyday existence was bound up with it and dependent upon it. We can understand that a man living near the dykes would be bent down in old age through years of steady tramping, working, and toiling against the wind; that the Dutch from remote times were bound to become sober and stubborn men: sober because they always had to reckon with the treacherous elements, and stubborn because persistence alone could make them win. And any sailing-man who is alive to the grandeur of nature will be thrilled when - alone or with a few comrades - he feels at one with and a part of nature: wind and water and floating clouds; he takes a particular delight in the effort to keep his head above water in the most literal sense and make headway with primitive natural aids (for a sailing vessel after all is essentially a primitive means of transport). This also makes it understandable that a fisherman is bound to follow his primitive urge and would not exchange his precarious subsistence for any other trade, but wants to remain skipper, next to God, on his boat, as it says in the ship's papers. Fishermen and farmers themselves have become part and parcel of nature, men of few words, good company, for all their different intellectual level. And anyone with a sense of poetry will have his head filled with a world of thoughts when he listens to the whistling of the wind, either through the rigging or - when sitting by the hearth in a lonely farmhouse - down the chimney, or in the groaning and moaning windmill which, indifferent to the elements outside, works and toils, its interior only sparely lit by a dim and flickering lamp.
In former ages the wind was utilized by the Dutch to satisfy their daily wants: keeping the soil dry, in order that they might cultivate it, and grinding the corn harvested as a result of their labour and daily care. Nor did they stop at the satisfaction of the most primitive daily needs; indeed, wind and water became the factors that helped Holland to attain to glory and prosperity: water as a medium for cheap long distance transport, the wind as a driving power for the sailing vessels and for the numerous industrial mills with which Holland abounded in the seventeenth century.
Viewed in this way, they carry our thoughts back to the remote past, these windmills which saw so many generations come and go, which in their unspoilt beauty absorbed and preserved, as it were, something of the spirit of the past generations, with their toil, their joy, and their grief. The windmills to us are symbolic of daily human labour, their sails turn round in sunshine and rain, in the biting cold of a winter's day, in the bright spring skies as well as in the heat of summer.
The windmills belong to the Dutch landscape, to such an extent that we cannot imagine this landscape without them, at least not without feeling that something valuable is missing.
This is how Henri Polak describes the Dutch polder land in his wonderful book Het kleine land en zijn grote schoonheid (The Small Country and its Great Beauty), how in a few sentences he evokes a Breughel or Koekkoek picture:
'Then winter comes and the fields are buried under the snow; the wide plain is an endless white expanse, which on the vaguely discerned horizon merges into the leaden sky, or lies glittering fiercely in the brightness of the afternoon sun.'
And he continues:
'And if the winter drags, if no frost, storm, snow, and lashing rain are forthcoming, the farms and cottages lie quiet and dejected in the barren land and the only things alive are the windmills, which free the polder of excess water and keep it habitable and fit for agriculture, the windmills, whose strong sails catch the force of the same wind that beats down the rains and utilize it to deliver the polder of the mischief those rains might produce.'
From ancient times the windmills were a creation of the human mind, which differs from that of the brute beasts; they can indeed follow their instincts, but cannot produce efficient tools by the effort of their brain. The creative powers of man are characteristic of his mental apparatus and his affinity with a Supreme Being. Among the products of the technical ingenuity of man, windmills in their primitive shape and appearance will appeal even more purely and directly to our feelings than the later discoveries of technical skill, such as radar-controlled or automatic-pilot aeroplanes.
One should therefore be conscious of owing the windmills a debt of gratitude of more than a couple of centuries.
In old prints of towns and villages we often find numerous windmills. This is quite natural, for such prints give a more or less faithful picture of reality and the windmills were actually there. Anyone looking at such a print of Amsterdam or Leiden will be surprised to see the large number of windmills on the ramparts, which, when viewed from the environs, must have entirely dominated the silhouette of the town.
This large number need not surprise us when we bear in mind that in former days for every 2,000 inhabitants there had to be one windmill to ensure uninterrupted supply of meal to the population.
A painting reveals to us in particular how the artist was impressed by the windmill as part of a landscape or a townscape. If we have not yet recognized this quite so clearly in reality, the painting will confront us directly with the essential fascination exerted by a windmill on its surroundings. Just as in a well-painted portrait, it shows us the true character of that which the painter put on the canvas - its deeper meaning.
Frozen Canal near Dordrecht, by CH.H.J.Leickert
Just let us have a look, for instance, at the Frozen Canal near Dordrecht, by Leickert, one of the painters of the Romantic School of the middle of the last century. In the foreground we see a post mill, then two smock mills, and in the background a tower mill with a stage. Like the artist himself, we are affected by the harmony and the peacefulness inspired by the imposing windmills in the scene, in which the lively pattern of the skaters on the frozen canal fully harmonizes with the peacefulness of the whole picture. Look at the splendid pictures of Schelfhout, Nuyen, Koekkoek, and others, where windmills form the outstanding features in the wintry scene.
Take a Schelfhout, for instance: by the side of the frozen water a windmill is standing, immobilized in the wintry cold; drifting snow blows about the old woman with her wrap, who is straining against the cold wind on the country road, the snow covering the mill's cap like white powder.
In winter windmills look quite different from their appearance in summer; for contrast, have a look at the pictures of Roelofs, Gabriël, and Weissenbruch, which show them to you in the glorious light of summer, in the midst of fields, plants, and foliage at the water's edge.
Windmill at the Gein, by W.Roelofs
In the numerous museums of Holland you will find such pictures in which windmills figure: in the Rijksmuseum of Amsterdam, in the museums of Rotterdam and The Hague, and in a great many other towns. If you are interested, visit them and revel in the beauties of the old Dutch windmills as they have fascinated artists for several centuries past.
It was by no means in the 'Romantic' School alone that a great many works of art centred about the windmill or made it the main motif of the composition. With the great seventeenth-century masters, too, the windmill frequently appears on the canvas; we refer to the pictures of Averkamp, Ruysdael, Hobbema, and many others, as well as to the well-known etchings of Rembrandt.
It is hardly saying too much to assert that windmills must not disappear from the Dutch landscape, that their loss would impair the beauty of Holland irreparably, and that it would even amount to an 'international calamity', as a well-known American expressed it many years ago.
Many factors of a historical and an aesthetic nature play a part in this matter. It would have been a thousand pities if the appreciation of the great value of this national heritage should be lacking and if a foolish demolition mania should destroy the windmills. Fortunately these monuments are now protected by the government, by societies, by foundations, and by private person.
WINDMILLS IN DUTCH HISTORY
Windmills are said to have existed in Holland from about 1200. The first record we have of drainage mills dates from 1414 (Reijerwaard). Before those days, windmills are mentioned, but these must have been corn mills.
From time immemorial, wherever the land was inhabited, corn was grown. And where corn was grown, it also had to be ground to make possible the preparation of that excellent human food: bread. In the most primitive stage the corn was ground between two stones which were operated by manpower. The nations in the Bible already knew mills, operated by 'virgins': in Ecclesiastes 12 : 4 we read: 'and the doors shall be shut in the streets, when the sound of the grinding is low'. The excavations at Herculaneum and Pompeii too have revealed bakeries with millstones.
In later ages cattle power was employed, as in the horse-mills, and finally the forces of nature were harnessed: wind and water. This latter method already called for some technical knowledge; the water mills, which naturally occurred only in the eastern and southern parts of the country, probably existed before the windmills, for their construction was simpler.
Towards the end of the eighteenth and in the early part of the nineteenth century the discovery and application of steam power caused a radical revolution in social economy, and this initiated the end of the supremacy of windmills as prime movers for all purposes.
In the nineteenth century there were about 9,000 windmills in Holland; all these turning sails and the general activity to which they bore witness must have produced an overwhelming and unforgettable impression on the Dutch themselves as well as on foreigners. They imparted a special character to the country. In the Zaan district alone 900 windmills were working virtually night and day; they powered the industries of those days, and they were the precursors of the later big foodstuff industries, the paper works, and the saw-mill yards which exist there to this day.
From ancient times the so-called manorial rights included the milling soke, i.e. the right to permit or refuse the building of a windmill, to compel the tenants to have their corn ground at the mill of the lord of the manor, and to prohibit buildings or trees in the vicinity of the mill, so as to ensure a 'free wind'. In a letter dated the Thursday after St. Nicholas's Day of the year 1299 John the First, Duke of Brabant and Limburg, grants to Arnoldus, named Heyme, as an addition to the territory the latter held in fee from him, the right to erect a windmill between the village of Hamoda van Rode (Sint Oedenrode) and Skinle (Schijndel), in the place which he should consider the most suitable, and for this purpose grants to him the hereditary right of free wind. From this document it can be inferred that the building of a windmill was certainly nothing out of the common in those days. Indeed, as early as 1294 the Count of Gelre paid an account which appears to relate to repairs to a windmill.
In the years following, the entries relating to windmills grow more numerous: old gunpowder towers which passed into disuse were converted into (so-called tower) mills, and on the walls surrounding the towns many windmills arose. We see them in numerous old prints and engravings, views of towns, maps, and street-plans. Usually these are post mills, and occasionally a tower mill.
When we look closely at the print of Jacob Savry, the windmill on the extreme right is De Koe (the Cow), standing near the Koepoort; to the left of this, the mill De Kaaskorf (the Cheese Basket). The two mills to the left stand on the Groote or Blaauwe Bolwerk, the site of the present Astronomical Observatory of Leiden University.
The water-gate visible between the two first-mentioned windmills, the present Vlietbrug, is the gate or bridge through which the Geuzen (Beggars) entered at the relief of Leiden, in 1574.
On the extreme right of the print we see the gallows, to which the water, called Galgewater, owes its name.
In those years of sieges corn mills, which naturally at first were to be found mainly in the country, began to be concentrated in the towns; they were erected on the outside walls of the walled towns, so as to catch the wind.
In the bottom lefthand corner of the engraving the dedication is given to the Honourable Sheriff Gerard van Hogeveen and to the four burgomasters - mentioned by name - of the town of Leiden.
The oldest known document containing a reference to windmills is considered to be the privilege which was granted to the burghers of the town of Haarlem in 1274 by the Count Floris V. There are also data about windmills in Amsterdam, dating from 1336 and 1342, in Utrecht, dating from 1397, and in other towns. In The Hague, on the site of the present Molenstraat, there was a windmill, the Nortmolen (1316), and another on the site of the present Westeinde (1351).
But the real development of the windmill will have to be sought towards the end of the sixteenth and in the seventeenth century; this development was quite stormy.
The many industrial mils in the Zaan district and elsewhere were built with heavy timber, brought by the sailing vessels from the countries on the Baltic Sea.
From the original types, such as the open and closed post mills, arose the wipmolen (hollow post mill) and the classical drainage mills, the large corn mills, and all those other industrial mills with which Holland abounded. To begin with, in the Zaan district there were the oil mills and the paper mills. Where the timber for the many houses and ships to be built was imported for sawing, were to be found the characteristic paltrokmolens. These owed their name to the flaring coats, the Palts-rokken, worn by the Mennonites who had emigrated to the classical country of liberty, and particularly to the Zaan district.
The paltrokmolens, with the wings added to left and right forming part of the working-space, can be turned as a whole to face the wind, so as to make sawing possible irrespective of the direction of the wind.
In those days windmills were as important for Holland as are the numerous factories in the industrial regions nowadays. The invention of the art of printing had started an enormous demand for paper; the importation of colonial produce had given rise to great activity and prosperity; new arable land had to be drained and opened up, and everything contributed to the high tide of the Dutch golden age.
In the period up to about 1000 A.D. Holland could hardly be called habitable; it consisted of marshes with small sluggish streams, separated from the sea by a belt of dunes, and the inhabitants had to hold their own mounds. It was only after 1000 A.D. that they succeeded in checking the water to a greater extent. In the raw climate prevailing in these parts they had to keep warm by burning dried peat and wood from the neighbouring forests. Their existence in those years must have been extremely rough and distressing indeed. In the period up to 1400 the centres which led to the rise of the towns were formed. The land was repeatedly ravaged by floods, when large tracts were swept away and disappeared into the sea; inland seas were formed (the Zuiderzee was formed thus about 1300), villages were destroyed, and great were the losses in goods and chattels and human lives. A notorious flood was the St. Elizabeth's Flood, from 18 to 19 November 1421, when in a single night 72 villages and hamlets were swallowed up by the water and thousands of men, women, and children with thousands of cattle met their death in the waves.
After 1400, when major sea-defences had been first constructed and the communication of several waters with the open sea had been dammed up, it became possible to drain pools and lakes. For this purpose windmills were used, and accordingly were built in constantly increasing numbers. At first these were not yet the large mills as we know them, which date especially from the seventeenth century, but smaller mills of the hollow post-mill type.
As windmills grew better and larger their water-lifting capacity increased and they became more numerous. According to the records it was about 1526 that a wip mill was replaced by an octagonal smock mill with a revolving cap. This must have had a winch in the cap, for it was not until the second half of the sixteenth century that smock mills with tail poles were constructed. After that, the possibilities increased rapidly. We find entries about the first oil mill in 1582, a paper mill in 1586, a timber sawmill in 1592; after 1600 windmills arose everywhere and were constructed for a wide variety of purposes.
In the seventeenth century the Dutch made more and more progress in the fight against their hereditary foe, the water. It is a fight that has had to be continued every day and the windmills have played an all-important part in it for more than two centuries. They delivered the country of the water and kept it dry, in spite of the fact that it lies several feet below sea level; in this way they made and kept it habitable. Holland owes its creation as well as its development in the most literal sense to the windmills, for it was thanks solely to the windmills that is was possible repeatedly to reclaim new land for the ever growing population.
The land between the towns of Holland consisted largely of peat-bogs. These bogs were of the utmost importance. How else were the inhabitants to heat their houses in winter in a country which had no coal fields, while wood from the forests could only be brought from remote regions? The peat around the towns and villages therefore was generally cut away, and as greater depths - and thus water - were reached the peat was scooped out, dried in summer, and burned in winter.
Because such peat-cutting took place on an ever increasing scale, new pools and lakes were formed in addition to the original ones and the expanses of water grew larger and larger, particularly because the water lashed by the wind tended to encroach more and more upon the banks. The lakes were becoming a great danger to towns such as Amsterdam, Haarlem, Alkmaar, and Leiden, and the necessity of draining the peat-bogs was growing more and more urgent.
It was in the years between 1608 and 1612 that the Beemster was drained. This lake had a depth of ten feet and it was drained in one year with 26 windmills, working in two stages. But the Zuiderzee dyke burst, the new ring-dyke was unable to check the water, the polder filled up, and the work had to be done all over again. In 1622 the Purmer followed, in 1625 the Wormer, and in 1629 the Heerhugowaard. In all these projects and activities the renowned hydraulic engineer Leeghwater took a very active part. In 1631 the States of Holland and West Friesland granted to the town of Alkmaar a patent for dyking and draining the Schermer according to Leeghwater's plans. For this purpose the polder was divided into 14 plots, each with its own mill. These 14 mills pumped the water into a storage basin, from which the water was pumped into the ring-canal by means of 36 mills, twelve sets of three working in stages, in order to raise the water to the high level. Altogether 51 mills (of which one served for a separate plot at a higher level) worked in this polder and they pumped out water at a rate of 1,000 cu.m./min. In four years the polder had been reclaimed and the soil could be cultivated.
The mills in question were smock mills, the familiar large octagonal wooden windmills of the North-Holland type; the span of sails, i.e. the total length of a stock (over twice the length of one sail), was 90 to 100 feet. This length formed the limit, in view of the length of the tree-trunks from which they could be made. For the same reason the wind shaft was tied down to a maximum section of about 2 x 2 feet; heavier timber was not available!
JAN ADRIAENSZ LEEGHWATER (1575-1650) was a great man. Born at De Rijp, a village in the midst of the pools and lakes of North Holland, he started life as a carpenter and millwright. He was a born inventor, engineer, and constructor, and became a renowned hydraulic engineer and dykebuilder. An invention of his enabling a man to remain under water for a considerable time caused something of a sensation and he demonstrated it before Prince Maurice, in the presence of the famous Simon Stevin.
Technology appealed greatly to Prince Maurice, for - just as at present - it was needed in the military sphere. Conversely, technology was stimulated by the circumstance of war and Prince Maurice sought the assistance of the famous SIMON STEVIN, of Bruges (1548-1620). Stevin was a great mathematician, who, among other things, drew up tables for the calculation of compound interest and applied exact calculations to engineering construction. Many patents in his name exist, among them some for the improvement of drainage mills. It was on his initiative that Prince Maurice founded a 'School for Fortification Engineers' at Leiden University in 1600. A fact more generally known is that Stevin sailed along the beach from Scheveningen to Petten with Prince Maurice and some distinguished personages in a sailing chariot or sand yacht.
Prince Maurice later also consulted the much younger Leeghwater, the man who had drained the Beemster and who excelled in all sorts of engineering techniques. He had also built two 'notable chimes', one in the Westertoren and one in the Zuiderkerkstoren in Amsterdam.
After the reclamation of the Beemster, Jan Adriaensz Leeghwater became the regular advisor of Prince Maurice and Prince Frederick Henry. His advice was also asked abroad, both in Holstein and in Flanders, in France as well as in England.
Frederick Henry employed him during the siege of Bois-le-Duc. The position was defended by the enemy by means of inundations and the Prince called for Leeghwater to remove the water; he did so by using horse mills and windmills.
In his old age he recorded his experience in two booklets, which have become quite famous; in his earlier years he would hardly have had the time for writing! He conceived a bold plan for draining the large Haarlemmermeer, which had a depth of 13 feet, with the aid of 160 windmills. This famous study appeared in 1641 and was soon out on print. It was in such great demand, even after his death, that the book passed through seventeen reprints (seventh edition in 1710, thirteenth edition in 1838). Several plans were made after that time, but it was not until 1848, when steam engines from Cornwall in England were available, that the great work could be executed; it was done as a state enterprise.
In 1579, with the Union of Utrecht, the various provinces entered into a kind of confederation, forming together 'The United Provinces'. A greater unity arose, without the independence of each province being too greatly impaired. The frequent quarrels and squabbles gradually came to an end, and the prosperity of the country increased greatly. The East India Company was formed and in every direction new trade routes were opened up. Availing themselves of the wind, the Dutch sent their sailing ships across the oceans to remote countries, thus becoming 'the sea-carriers of Europe'.
The product brought home from the 'Colonies' were sold and processed in Holland. The latter again was possible entirely thanks to the windmills. Manpower or horse-power was insufficient, just as for the pumping of the polders and the drainage of the lakes; rivers or brooks with a fall sufficient to supply the requisite power for industrial purposes by the use of a water-wheel did not exist in Holland. The only natural source of power available in these regions to an abundant degree was the wind.
This natural form of energy, which was freely available every day, was utilized by the inhabitants on a huge scale; because of this, the construction of windmills was raised to a high degree of mechanical perfection.
It has been stated above that the Zaan district, the flat country lying to the north of Amsterdam between the North Sea and the Zuiderzee, was the industrial mill district par excellence. Besides the types already mentioned, a wide variety of industrial mills existed in Holland: barley- and rice-hulling mills, cocoa mills, snuff mills, pepper mills, oil mills, mustard mills, dye mills, chalk mills, lime and trass mills, fulling mills (for the treatment of cloth), and tan mills for grinding oak-bark for the tanneries.
The acquisition of new fertile land and the large-scale industrial processing of the products, in combination with shipping, gave rise to an unprecedented prosperity, which was reflected in the flourishing of the fine arts, in particular the art of painting. The well-to-do merchants commissioned architects to build fine houses, and they wished to furnish them with handsome cupboards and with porcelain which the ships brought from China, and to adorn them with pictures and portraits painted by famous artists. It is not without reason that the seventeenth century is known as the Golden Age in the national history of Holland.
THE TYPES OF WINDMILLS
Anyone reading, speaking, or writing about windmills is almost sure to think of the famous story of the Knight of the Rueful Countenance, Don Quixote de la Mancha, on his Rozinante. The sedate country squire who, having lost his head after reading a great many romances of chivalry, proclaims himself a knight errant and induces a poor peasant, Sancho Panza, to leave his wife and children and, seated on a donkey, accompany the knight as his shield-bearer on his odd expeditions.
They set out together and in the plain find a large number of windmills, which our knight takes for uncouth giants and accordingly has to fight. Lance in rest, he rushes at them, with the consequence that the turning sails cause him and his jade to roll over the plain. These mills had a cylindrical stone body, covered with a conical roof; they had four wooden stocks with frames on both sides.
The windmills of the type still to be found to-day in the regions of the Mediterranean, with five, six, or more primitive sails consisting of bars rigged with jib sails, in comparison with the Dutch windmills are also only humble wind machines.
But we will confine ourselves to the Dutch windmills, which are characteristic of the country and whose perfection and gracefulness are not surpassed by any other type, in any part of the world.
During our excursions through Holland, by train, by car, by bicycle, on foot, or - better still - in a wherry or a sailing-boat (for Holland is still most beautiful of all when seen from the water!), we shall see windmills, and in some places even very many of them together. They still exist indeed. It is true that they are no longer as numerous as they used to be, but close on one thousand of them are left. That the mills are still there is largely due to those who about 1920 took the initiative in fighting against the neglect of the windmills and the rage for demolition which assailed them from every side at that time. Owners who did not replace their windmills by mechanical pumping stations were considered old-fashioned, those who spoke in favour of windmills were called idealists not amenable to reason; neither the importance nor the value of the windmills in their technical, cultural, or artistic aspects were recognized any longer.
In 1926, under the leadership of Dr. P.G. van Tienhoven, a Dutchman of stature, the champions of the preservation of windmills in Holland published a pamphlet by which they opened the eyes of many people and solicited their membership of De Hollandsche Molen (Dutch Windmill Society), set up in 1923.
The efforts of these men made a considerable impression at that time. From every side people gave their sympathy and aid, so that in course of time the society was able to make its influence felt and to enlighten the general public; it developed into an organization which combined all efforts to preserve windmills.
Thanks to these efforts windmills still exist in relatively large numbers and variety, thus confirming the view of foreigners that Holland is the land of windmills.
On your wanderings in Holland you will see these windmills and they will be sure to fascinate you. But your pleasure will be enhanced when you know a little more about them, when you learn to distinguish between the various kinds and types, and when you know some particulars about their function and, in connection with this, about the way they are built and work. We will attempt to give you an outline and propose to discuss first the different types.
Windmills can be classified in several ways, viz. according to their outward appearance, the way they work, and the task they have to perform. These classifications do not coincide, but they do overlap here and there. This has given rise to names which are not always very clear or unambiguous.
According to their outward appearance the following windmills can be distinguished: the post mill (standaardmolen), the hollow post mill (wipmolen), the large Dutch drainage mill (kloeke poldermolen), the smaller types of drainage mill, the tower mill with a stage (stellingmolen), the paltrok, and the cylindrical tower mill without a stage (torenmolen).
Smock and tower mills are called bovenkruiers (lit. upper winders) and are subdivided into binnenkruiers (lit. inside winders), whose caps are turned by a winch inside the cap itself, and buitenkruiers, which have the winch on the end of a tail pole. There are also beltmolens, built in mounds, and windmills whose towers rise straight from ground level; these latter are called grondzeilers (lit. ground-sail mills).
Finally windmills are classified according to the task they perform into drainage mills, corn mills, sawmills, and further a group of industrial mills all of which, with some variations, have more or less similar, factory-like interior equipment and comprise oil mills, fulling mills, paper mills, and the like.
All these classifications are to some extent arbitrary. A corn mill is usually a tower mill with a stage and a tail pole; if it stands on a town wall, it will also be called a walmolen or wall mill.
Again a wipmolen or hollow post mill is sometimes a corn mill, while on the other hand occasionally - though rarely - a drainage mill with a stage is to be found.
A paltrokmolen is always a sawmill, but there are also sawmills which are smock mills, nor is a small wipmolen on the roof of a barn unknown, which acts as a lattenzagertje (small sawmill in which laths are sawn).
All this seems rather confusing, but we will choose the most obvious method, showing the different types of mill as they appear at first sight, so that you may be able to recognize them from afar.
To see a POST MILL you will have to go to North Brabant, Gelderland, Zeeland, or Limburg. Some are still to be found there, but this, the oldest type, is almost extinct. The post mill is a corn mill, and large numbers of them are to be seen in old engravings.
The body of a post mill consists of a large square box, constructed to turn about a heavy wooden pillar - the post. The breast and the tail of the body are narrower than the sides, so that they may catch as little wind as possible,
Arrangement of the drives in a post mill
while still providing sufficient space inside. The body is turned to enable the sails to be set into the eye of the wind with every change of direction.
The post is supported by a system of double quarterbars and heavy crosstrees resting on brick piers.
The mechanism is accommodated inside the body: two wooden gear wheels on the wind shaft drive two vertical spindles and rotate the millstones in their casings. As a rule the machinery is distributed between two floors, with one set of stones on each floor. It is not complicated and its operation is plain from the diagram. Details of the lay-out of a corn mill will be given later on.
Exterior of a post mill tail, breast and side elevation
The body is raised a considerable distance above the ground, for the sails should have a certain length if they are to reach well into the sky and catch sufficient wind. The wind pressure not only drives the sails round, but also exerts a rearward pressure on the sails and thus on the whole body of the mill. This pressure is taken mainly by the post, aided by the tail construction. At the rear of the mill a broad oaken ladder descends from the body to the ground; further there is a heavy tail pole which - being connected to the framework of the floor of the wooden body - extends from there backwards. This tail pole passes between two rungs of the ladder and then curves slightly downward, while its end is firmly fastened to the end of the ladder by means of two upright oaken posts. At the bottom of the ladder the winch or the winding wheel can be operated. This heavily constructed system of ladder and posts form a counterweight for the great weight of the stocks with the sails, so that everything is balanced. When the mill is working, the ladder with the tail structure may rest on the ground and thus help to take the pressure of the wind on the sails and the mill body. The mill body can be reached from the ground along the ladder.
In the simplest construction the supporting system of crosstrees and quarterbars is open; in this case the mill is called an 'open post mill'. If the base is enclosed and thatched, the system of crosstrees and quarterbars is protected from the weather, and a kind of primitive storage place is obtained; the mill is then called a 'post mill with a roundhouse'.
At the rear of the mill body is a balcony with a handrail, reached by the ladder, and here is the door which gives access to the mill body. Over the doorway there is a fair-sized opening with a shutter and at the top of the tail a pent roof or the like, the shape of which differs according to the region in which the mill is situated and which protects the sack hoist from the weather. The 'sack hoist' is the apparatus for hoisting and paying out the filled sacks and consists of a wooden shaft, which can be coupled to the wind shaft inside the mill and projects from the tail at the back. With the aid of this device the sacks can easily be hoisted by wind power.
In the sides of the mill body are a couple of vent-holes, which can be closed by shutters. When the wind starts to blow through a hole, it warns the miller that its direction has changed and that he should turn the mill. The front of the mill body, called the breast, is usually adorned with a 'prick post' and the lower edge is gracefully curved.
These post mills are very curious wooden structures of considerable antiquity.
The relative small space inside the post mill was not sufficient; the storage space was small, and loading and unloading always had to take place in the open. Hence, corn mills evolved in the direction of the larger mills built of brick. At first, use was also made of the round brick powder magazines found in the towns, which had fallen into disuse for the purpose for which they had originally been designed. These were the torenmolens (cylindrical tower mills).
The post mill is the type from which the wip mill (hollow post mill) developed; this is known to us chiefly as a drainage mill. In drainage mills the mechanism, the scoop wheel or the Archimedean screw, is of course always tied down to a fixed place on the ground and accordingly must not turn with the mill. The turning portion of the mill could therefore be smaller and in consequence more manageable. The base on the other hand became larger and developed into suitable living quarters for the miller.
The total number of post mills in Holland is no more than forty; so they should be carefully preserved. Handsome post mills are to be found in North Brabant at Nistelrode and Uden, in Gelderland at Nederasselt and the Doesburg mill near Ede, in Zeeland at Retranchement and at St.Annaland. There is also a good post mill at the Dutch Open Air Museum at Arnhem, but the appeal of such a mill is greatest in its own natural setting, in the midst of the corn fields. In the national park Buurserzand, in the municipality of Haaksbergen, you will find an open post mill in good condition in the midst of beautiful unspoilt scenery; the premises are owned by the Society for the Promotion of Nature reserves. There is yet another mill of this kind at Ter Apel in the Groningen region.
Hollow post mill
The drive from wind shaft to scoop wheel.
The brake wheel has 68 teeth, the wallower 35 staves; the crown wheel has 23 staves; the pit wheel has 95 teeth.
So the wind shaft has to make 2.12 revolutions for each revolution of the scoop wheel.
The WIP MILL is the graceful mill still to be found in great numbers in the polder regions, especially in South Holland and Friesland; wip mills are nearly always drainage mills and only a few wip mills function as corn mills.
All the indications are that the wip mill - the oldest drainage mill - evolved from the post mill. The square revolving upper part of the mill has now become relatively small, the stationary pyramidal base relatively large. The former has to accommodate nothing but the wind shaft, the brake wheel, and the wallower on the top of the upright shaft. The upright shaft in the centre of the mill extends vertically through the hollow post from the top to the bottom, where the weight is taken by a thrust bearing on the underframe. At its lower end the upright shaft carries the crown wheel, which meshes with the teeth of a large gear wheel, called the pit wheel. This pit wheel is fixed to the shaft on which the scoop wheel is mounted. In this way the scoop wheel is driven by the turning sails. The space occupied by the gearing in the base is fairly large, but the remaining space is often used as living accommodation.
Wip mills are generally painted in very bright colours and they provide a characteristic gay note in the polder landscape. The finest are those whose substructure is covered with the beautiful thick reed thatch protecting the dwelling, broken only here and there by a few small openings for the windows and doors. They impress us as a pattern of cosy domesticity, where in winter the inmates are effectively protected from the violence of the weather; they are in perfect keeping with the raw climate of the low countries, with its frequent rains, showers, and snow or hail storms. In summer, with their thin wasp-waists they look like dainty, gay damsels which, brightening up the whole landscape, are a pleasure to behold.
Wipmolen (hollow post mill).
Left: front view; Right: side elevation.
The wip mill, like the post mill, has a tail pole, ladder, and winch. A couple of additional braces consolidate the whole structure.
The lower portion of the wip mill has an entrance door in each of the two sides at right angles to the direction of the scoop wheel. These two outer doors are required in order to provide free access and exit with any position of the plane in which the sails are turning. The door past which the sails sweep is then kept firmly shut, for it would be highly dangerous if someone were to pass through inadvertently.
The wip mill, the first type of mill with which wind power began to be used for keeping the land dry, was developed in the early part of the fifteenth century. The mill was equipped with the familiar Old Dutch water-raising mechanism of simple construction: the SCOOP WHEEL. The scoop wheel may be mounted inside or outside the mill; in the latter case it is often enclosed in a wooden casing. Originally the wip mills were smaller in size and although they were made larger and larger, they have not the same dimensions and capacity as the larger drainage smock and tower mills, the sturdy fellows built later on, when greater experience had been gained and the task of draining the larger lakes and pools was undertaken. It is obvious that the size of the scoop wheel should vary with the length of the sails employed; its size has to be adapted to the capacity of the mill. We cannot therefore fail to be impressed by the considerable knowledge and practical experience which the millwrights of the early days must have possessed, since they were able to construct everything in proportion empirically and without calculations!
It was not until much later that besides the scoop wheel the Archimedean screw came to be used to raise water; it does not seem to have been adopted for use in windmills until about 1634, and in this connection the name of Symon Hulsbos is
The body of the wipmolen.
Left: tail with door and gable; right: breast with vertical prick post
mentioned. An 'invention' in the true sense of the word it can hardly be called, for Archimedes already knew the cochlea and it is natural to assume that it will have been used before - with hand-power - to drain deep pits or for similar jobs, which undoubtedly regularly had to be done during building operations in the watery regions of Holland.
Here again there is a striking analogy with developments in the sphere of shipping. The scoop wheel was the most obvious mechanism for raising water; it was also the most obvious means of propulsion for ships. In the case of windmills the scoop wheel is in a fixed place and the water is moving, in the case of ships it is the other way round: the water remains, as it were, in the same place, but the ship is propelled. In 1805 the first paddle steamer was put in service and it was only in 1836 that screws were used for propulsion and the ship's propeller was 'invented' by the Swede Eriksson. The ship's propeller is after all nothing but a modification of a section of an Archimedean screw and the paddle a modification of the water wheel.
Whilst in the post mill the body is able to turn about a solid pillar because as the mill body moves the mechanism inside turns as well, in the case of a wip mill the top had to be able to turn without interfering with the transmission from the wind shaft to the scoop wheel. To make this possible, instead of the solid wooden shaft a heavy hollow wooden post is made, about which the top can turn; through this post the shaft is passed. Hence the wip mills also used to be called kokermolens (hollow post mills).
The arrangement of the wip mill is fairly simple; by reference to the diagram its working can easily be understood. About midway the wind shaft carries a large gear wheel, the brake wheel, which drives an upper gear wheel on the upright shaft, the wallower. The latter may be constructed as a lantern wheel with staves mounted between two disk-shaped flanges or as a trundle wheel with cogs mounted in one wooden flange. Fitted round the rim of the brake wheel is a large-sized band with brake blocks, which can be clamped on to the wheel by means of the brake lever. When the brake handle is operated, the brake lever moves from its position at rest, so that by its own weight it contracts on the brake blocks, thus producing the braking effect.
The other components of the wip mills are similar to those of the larger drainage mills; we will revert to them later on.
The living accommodation inside a wip mill is not very large and hence a small cottage, the summer house, is often found close to the mill. It is there that the miller and his family live more comfortably in summer. The summer house is low, so as not to interfere with the catching of the wind. The smaller wip mills are not inhabited.
When the need of larger and more powerful windmills began to be felt, the large DUTCH DRAINAGE or POLDER MILL was developed. It is called a bovenkruier (cap winder), but the name is an indication of the variety rather than a name for a particular type.
These large drainage mills were developed in the watery region of North Holland in the second half of the sixteenth century. They evolved logically from the wip mills when the top was made smaller and the mill body proper larger, in consequence of which the mills could generate a much greater power while still remaining manageable. The larger construction also provides more suitable living accommodation. These mills soon ousted the wip mills in the fight against the water.
The cap is turned in the top of the mill on the inside with the aid of a winch with a hand-wheel or a handle.
It is a constantly recurring and fatiguing job for the miller to go upstairs to turn the mill whenever the direction of the wind changes. The further development of these large mills therefore was in the direction of making it possible to turn the cap from below, viz. on the outside by means of a TAIL POLE. Thus arose the familiar large mill of South Holland.
It is curious that in spite of this ease of handling of the buitenkruier or outside winder the unchanged North-Holland type yet has held its own to this day and the type has been preserved as the binnenkruier or inside winder. Outside the province of North Holland this type does not really occur, but several drainage mills in South Holland still show signs that they must once have been inside winders.
Large octagonal drainage mill or polder mill, South Holland type, with
internal scoop wheel.
The tower in front elevation, the lower part in section, to show the working of the scoop wheel.
The only type found in South Holland is the outside winder, the familiar large classical drainage mill or octagonal mill.
The space inside the cap of the outside winder can be smaller than is necessary in the North-Holland type and this is clearly visible from the outside. The appearance of the North-Holland mill is more solid and less elegant, but it is very sturdy, powerful, and tall.
The large South-Holland type mill not only has a smaller cap, but also a tapered form, so that it is more elegant, while moreover it has a rakish tail and owing to its gracefully curved lines makes a much more handsome impression; the inside winder always strikes us as rather 'bare' and uncompromising.
A further outward difference to be noted is that the windmill of the North-Holland type has a wooden base which is higher and is covered with overlapping boards which are tarred or painted. The base of the South-Holland windmill is somewhat less high and built of brick. The body of both types is usually thatched.
The two types therefore can be easily distinguished from a distance. Their interior machinery and operation are practically identical.
The base of the large drainage mill is usually built in the form of an octagon. Supported on this octagon is the wooden structure, consisting of heavy timbers, vertical and horizontal, joined together by sturdy diagonal beams and joists of the various floors. A rigid unit is thus formed; this is necessary indeed, for it sometimes has to withstand considerable force.
The beautifully curved hollow lines of the mill body, so satisfying to our aesthetic sense, also have a definite practical reason: the wind from the descending sail in this way meets with less resistance.
Plan of a large octagonal drainage mill
There are also mills made entirely of brick and they are sometimes six- or twelve-sided, and often also perfectly circular. However, it is not surprising that in Holland, with its soft subsoil, thatched mills built of wood were preferred. These are much less heavy than mills built of brick, Besides, in the Dutch climate it was always difficult to keep a tapering brick wall properly watertight.
The materials wood and reed have held the field up to the present day. They are quite appropriate in the Dutch countryside and climate; good oak timber will last for centuries, as witness the oaken staircases and beams in the handsome houses of the old towns. Timbers covered with reed have always furnished structures fully meeting all requirements of insulation, combined with ventilation, long before the days when this had to be deliberately sought in present-day materials. The same can also be seen in Dutch farmhouses; from the aesthetic point of view it is hardly possible to imagine anything more handsome in this respect.
Construction of the mill body
In the cap of the mill, slightly inclined to the horizontal, lies the heavy wind shaft, the front journal turning in the neck bearing, supported on a wooden block, called a pillow block. At the tail the shaft is supported in a combined journal and thrust bearing. Early bearings consisted of a simple hollowed-out piece of freestone, which was lubricated with tallow. At the present time ball journal and thrust bearings are often used.
The front end of the shaft (the poll end) projects from the cap and the stocks pass through it. The wind shaft is a very heavy wooden or iron affair of some four or five tons. To raise it to the top of the mill and locate it in its bearings without the aids and appliances nowadays available is a difficult and even dangerous job, which can only be accomplished successfully by highly experienced and capable skilled millwrights.
For the rest of the mechanism: upright shaft, brake wheels, wallowers, crown wheels, etc., reference may be made to the description of the wip mill. The gear wheels themselves are masterpieces of skilled craftsmanship; they are made of oak from the Balkans and of lignum vitae. Lignum vitae, besides its hardness, has the additional advantage of being to some extent self-lubricating. The gears mesh almost noiselessly and thus with a minimum of friction, having been made for many centuries by the method of trial and error.
It is pertinent here to say a little more about the function of the drainage mill in general and of the water-raising mechanism in particular.
The scoop wheel is a water-wheel and in its function for the 'transport' of water it may be compared with the wheel which, from time immemorial, has played such a big part in all transport by land: the ordinary waggon-wheel. Even outwardly the two resemble each other closely. If the spokes are imagined to have the form of broad plates (the floats), enclosed on both sides between the brick walls, trough-shaped spaces are formed; as the wheel turns each trough fills at the bottom, is moved upwards, and, when arrived at a given level, empties itself automatically. The outlet thus takes place at a higher level than the inlet, and in this way the water is lifted. The lift is naturally limited, since it is conditioned by the radius of the circular scoop wheel. On practical grounds there is a certain maximum size for the scoop wheel and this means that the water is not lifted beyond a difference in level of 4 feet, or at most 5 feet, by a scoop wheel.
How then was it possible to drain pools and lakes which often had a depth of 13 to 17 feet?
First a 'ring dyke' and a 'ring canal' would be constructed round the lake to be drained, and a number of windmills would be built in predetermined places, for the water to be pumped into the ring canal. When the work had progressed to the point where the level of the water was too low for the scoop wheel to reach it, it became necessary to build a second set of mills, which would start to drain the deeper part of the lake at a level some 5 feet lower. These mills would pump the water into a kind of intermediate storage basin or network of canals, from which the first mills pumped it into the ring canal again. Similarly a third and even a fourth 'stage' could be made if necessary, and thus the deepest pools could be drained. Each set of mills operating in series is called a molengang, a 'gang' of mills, and one or more of these have to be made, the number being dependent upon the size of the polder to be drained. There may thus be cases where pumping in stages comprises only three mills, which pump out the
Lifting in stages.
(three mills in series)
water one after the other; if the polder is not only deep but also covers a large area, more than one series of mills will be required. The mills pass on the water, as it were, from one to the other, and the last discharges it into the ring canal.
The water storage space required between the mills of different stages is formed by an intermediate storage basin; frequently a simple canal is used for this purpose.
The water that is continually pumped into the ring canal has to be removed and it is either drained off into one of the large rivers which carries it to the sea or direct into the sea. The number of discharge possibilities for a large area, however, is limited through natural conditions; in the old days the only possibility of getting rid of the superfluous water was the natural fall, i.e. at the times of sufficiently low level of the sea or river water. It was thus necessary for the water removed from the polders to be stored in a big reservoir until it could be drained off into the sea. Such a reservoir is called a boezem (storage basin) and it is formed by a complex of canals and lakes, of which the above-mentioned ring canal therefore forms part. It may temporarily hold a lot of water, and this is especially important in periods of great rains. Such a storage basin may cover a very large area in one or more provinces and it forms a separate unit. A waterschap (drainage district) has a board of its own; there are also Heemraadschappen (Drainage Boards) and Hoogheemraadschappen (River Boards).
Later, the construction of powerful mechanical pumping stations made possible a better control of the discharge of the water in the storage basin, so that this was no longer dependent on the caprice of natural conditions. Thus the Hoogheemraadschap Rijnland (the Rhineland River Board) has powerful pumping stations at Gouda, at Katwijk, at Spaarndam, and at Halfweg, by means of which the water is drained off either directly or indirectly into the sea.
While every drainage board is autonomous in its own area and authorized to make its own regulations (polderkeur), it stands to reason that the Hoogheemraadschappen also have their own extensive jurisdiction; they may also lay down rules to which the drainage boards have to conform. From the earliest times the drainage districts in Holland possessed sweeping powers, and this is indeed necessary, for the lives of the inhabitants, living many feet below sea-level, depend upon them!
All these drainage districts form peculiar autonomous areas with great influence in Holland. They have left their mark on the whole economy and the administration of the Netherlands as a land of polders, according to the ancient maxim: 'wien 't water deert, die 't water keert' (who is hindered by the water shall stem it). The specific character of the Dutch rural population, the landholders proper, and also of the Dutch people in general, their attachment to property and individuality, all this is closely connected with it.
Reverting to the scoop wheel of the drainage mill, we may observe that it is mounted inside in some cases and outside in others.
The water is fed from the polder by a large polder ditch, along which it is conducted near the mill to the scoop wheel between two brick-lined water walls. The scoop wheel fits accurately between the two water walls, pumps up the water via the water guide, and discharges it between the water walls to the ditch, mill race, ring canal, or whatever the name of the water may be. At the mill, the feed side of the water is called the intake, the discharge side the tail race. To prevent the water flowing back from the tail race to the intake during the periods when the mill is not working, the tail race is shut off immediately behind the scoop wheel by an automatic sluice door, which, in the same way as a lock gate, is closed automatically by the pressure of the water. As soon as the scoop wheel starts working, the dammed-up water automatically opens the door, so that it can flow off to the tail race. It is obvious that some over-pressure is required to open the door; this accounts for the fact that the mill does not displace water with the slightest movement, but has to reach a given minimum speed to keep the door open, although very little water, if any, is then displaced; the displacement does not start until the speed of the sails begins to increase.
The WATER SCREW (i.e. an Archimedean screw which is partly enclosed in a casing and is adapted to raise water) was used in drainage mills only from 1634 onwards. If such a screw is made long enough, it is possible to pump up water with it from a depth of 13 to 17 feet. This means a considerable simplification as compared with a series of three mills one behind the other. For deep polders and reclamation projects therefore Archimedean screws would often be employed.
One of the results of the competition held by the Dutch Windmill Society was the suggestion of the millwright A. J. Dekker to use centrifugal pumps in a drainage mill where the lift required is not very high. This was not a success after all; these pumps may sometimes involve too heavy a loading on the windmill. We have already pointed out before that the water-raising mechanism, the size and capacity of the mill, and the tensile strength of the parts, all have to be adapted very accurately to each other if unexpected unpleasant consequences are to be avoided; in the old windmills this relationship, well-tried through the years, is always present.
Arrangement showing method of driving the
Archimedean screw, of a drainage mill (after Krook)
The Archimedean screw is inclined downwards into the polder water; it turns in a brick-lined casing enclosing approximately one half of the screw, but open at the top. When it has reached the top of the screw, the water flows over a low sill to the tail race. A sluice door or trap, which is closed by its own weight as soon as the screw stops, prevents the water in the storage basin flowing back to the polder.
In the provinces of North Holland, Friesland, and Groningen many screw mills are found and few mills with a scoop wheel. In South Holland it is just the other way round: the scoop wheel has held its own there.
To prevent floating fragments of wood, tangles of waterplants, or accumulations of duck-weed from interfering with the operation of the scoop wheel or screw, on the intake side near the mill, i.e. on the polder side, there is a gate, which with its bars holds back any undesirable objects. It is the task of the miller to clean this gate regularly by removing the dirt; this is done from a plankbridge which has been built across the water intake along the upper part of the gate.
At its further end the scoop-wheel shaft carries a large gear wheel driven by the crown wheel on the upright shaft; this is the PIT WHEEL. It turns partly above ground level and partly in a bricklined culvert sunk into the ground. When the scoop wheel is built inside the mill, all these components, along with the upright shaft, occupy a considerable area on the ground floor of the mill, approximately one half of it. Next to this is the passage, and the other half of the ground-floor space is taken up by the living-room with built-in beds. Next to this, on one side are stairs leading to the first floor with the other sleeping-quarters and thence to the other floors; on the other side is a small ladder leading to the cellar.
Below is the storage space for fishing-tackle and the like, at least if this space is not occupied by the culvert in which the pit wheel turns and by the scoop wheel itself.
Owing to the shape of the mill and the way in which all the living quarters are fitted in, these rooms have very peculiar dimensions and make for a cosy, though somewhat primitive, interior. The living-room has fairly large windows, divided into small panes; on the upper floors small windows are let into the thatch. No fuss is made about the way in which the smoke from the hearth in the living-room is to be carried off: the chimney is extended some distance upwards inside the mill and discharges into one of the upper floors, whence the smoke has to make its way out as best it can through the chinks in the cap! Incidentally this has a great advantage: the woodwork is preserved marvellously well by it!
The genuine large octagonal polder mill of South Holland, with its brick base and thatched body, is the finest type of all.
Anyone interested in windmills should go and have a look at the magnificent group on the Kinderdijk. Sixteen large drainage mills are there grouped close together, a really fantastic spectacle. This mill complex of the Overwaard and the Nederwaard near Alblasserdam is of the greatest importance from the point of view of scenery as well as for historical reasons.
But other, smaller, complexes of windmills presenting a magnificent sight are also to be found in the heart of South Holland. When following the motorway from Gouda to The Hague, one will see on the left the four mills belonging to the Tweemanspolder under Zevenhuizen, a gang of four mills which make a fine spectacle as seen from the road and which are still in good condition, although they are no longer regularly in working order. Another complex, near Leidschendam, to be seen from the motorway from Ypenburg to Schiphol, consists of the three handsome mills of the Driemanspolder, which again are not in regular working order.
Anyone who wants to see a wonderful set of windmills still in working order should visit the gang of four mills of the Drooggemaakte Polder aan de Westzijde van Aarlanderveen (a drained polder to the West of Aarlanderveen); these windmills, situated in the municipality of Alphen aan den Rijn, are easily accessible from the road leading from the Aar canal eastward to the village of Aarlanderveen. They are each of them splendid mills, with their own picturesque setting and grouped together in an unique meadow landscape.
Besides the large polder mills (which pump some 1,750 to 2,000 cubic feet of water per minute) and the wip mills, of which there are larger and smaller specimens, there is yet another type, a kind of small wip mill, known by the name of SPINNEKOP (spider), a mill whose capacity is relatively small and which is equipped with an open Archimedean screw. The construction and equipment of this mill are wholly similar to the ordinary wip mill. The 'spiders' are mainly found in Friesland and the stationary base is there covered with rooftiles. The miller has to visit them regularly to control them, often from a considerable distance. The span of the 'spider' is rarely more than 30 to 40 feet.
It may sometimes happen that a few plots of land in a polder for some reason or another require additional pumping. In such a case a much smaller mill suffices and a WEIDEMOLENTJE (meadow mill) or AANBRENGERTJE is used. This need not pump the water into the ring canal, but discharges it into one of the polder ditches of the surrounding land. It is an even smaller specimen of the wip-mill type and it requires little attention, if any. These small windmills came into use in the course of the nineteenth century and at the present day there are still fair numbers of them in the province of North Holland.
At the back of the movable top there is a large, flat wind vane. Thus the mill will automatically face the wind and is always kept into the eye of the wind. The stationary base is an enclosed empty space; including the cap, the height of this mill above ground level generally does not exceed 10 to 13 feet and the span of the sails is in accordance with this. The water-raising mechanism consists of a simple centrifugal pump, usually three- or four-bladed, made of wood, which raises the water vertically.
Small meadow mill
Latterly instead of these small windmills the ugly iron aeromotors with a pump were used. Still, in the long run they were found to involve some disadvantages, so that after World War II the wooden windmills came into their own again. In order to keep the cost low, they are now made to a more modern design, although the old characteristic shape has been retained. The base is of concrete and thus requires no maintenance at all. Mounted on this concrete base is the pyramidal body, made of wood, with on the top a winding gear running on ball bearings. The sails have only boards and no sail-cloths.
The revolving top therefore is very easily turned to face the wind; this is brought about by the familiar large wind vane at the back, and the whole mechanism runs very smoothly. The construction of the wind vane in these modem windmills has the additional feature of a gale-safe device: in stormy weather the vane flaps aside altogether against spring action, and thus moves the sails out of the wind. The mill then stops and cannot be damaged by the gale. When the gale is over, the vane has to be readjusted to its original position by hand. For the rest this mill does not require the slightest supervision; the whole mechanism runs so smoothly that the sails need no cloths; the wind shaft as well as the upright shaft turn on anti-friction bearings. The rare occasions on which some one has to go up to the mill to readjust the vane provide sufficient opportunity to check whether everything is still in good order.
Finally there is still a small windmill of the simplest construction conceivable: the TJASKER.
The simplest drainage mill: the Frisian tjasker
This is found almost exclusively in the province of Friesland, and even there only very few specimens exist.
Properly speaking, it merely consists of a continuous inclined shaft, the upper end of which carries a set of sails, while the lower part ends in a closed Archimedean screw. A casing is thus not even required. The bottom of the screw is immersed in a deep pond, which communicates with the polder water via a culvert. The stocks have a length of 17 to 20 feet; they carry the common sails with leading boards and cloths. On the shaft a brake is present.
The legs of the trestle rest on a circular wooden beam, which sometimes lies loosely on a ring of concrete fitted round the pond; in this way the trestle can be turned round on this ring, the pole in the centre of the pond acting as pivot. The turning of the tjasker is a rather heavy and cumbersome job; as a matter of fact, the whole thing is extremely primitive. It is therefore not surprising that these mills have fallen entirely into disuse. But they are very curious indeed.
The STELLINGMOLEN or tower mill with a stage can easily be recognized from a distance; it towers above other buildings, the hideous tower flats of recent years excepted!
Owing to the need of additional working and storage space, about 1604 Dutch millwrights started to build large and tall mills; these were able to catch the wind across other buildings and did not have to be erected on the outskirts of the towns, where the walmolens or wall mills used to be placed. In villages, too, the tall windmill was useful, for there it was the trees which, in addition to the houses, tended to interfere with the free wind, while the large space inside the mill was also quite welcome there.
In the polders and the flat fields there is no difficulty in catching the wind and the drainage mills therefore are not very tall; they can be operated from ground level, they are grondzeilers (ground-sail mills). With tall windmills the cap is sometimes at a height of more than 100 feet and a special provision has to be made to enable the miller to get at the sails so as to set or reef the cloths, to turn the capstan wheel of the tail pole, or to operate the brake rope. This provision consists of a CIRCULAR STAGE with a HAND-RAIL, which is built round the mill tower halfway up.
The stellingmolens are familiar to us as industrial mills and corn mills. It is only rarely - as at Haastrecht - that a tower mill with a stage is used as a drainage mill. On the other hand there are corn mills built as grondzeilers, where wind conditions are such that a tall mill is not necessary.
The stage dominates the outward appearance of the mill entirely, and that is why it is often called a STAGE MILL. They are huge structures; their height is properly appreciated when they are seen in the midst of the town houses, as at Schiedam, for instance.
The tall construction is eminently suited for corn-milling; there are as many as six or seven floors and each floor can be used for a separate part of the process. The grain is hoisted up in sacks to the bin floor; this is done quite simply by means of the sack hoist, which is driven by the wind power. The grain then flows by gravity from the hoppers to the stones on the stone floor, where it is ground. The meal flows to a lower floor, the meal floor, where it is collected in sacks. Below the meal floor are the grain floor and the grain store.
The stone floor or the meal floor, or a combination of the two, as a rule is to be found at the level of the stage; the latter can only be reached from the inside.
Above the bin floor is the dust floor, and above this the top floor in the cap. On the dust floor there is sometimes an awful mess: dripping oil, dust, smoke from the chimneys whirling round there before escaping through openings and chinks, so that the miller enters this part of the mill only when necessary.
In the lower part of the mill the first - and sometimes the second - floor form the living quarters for the miller and his family; this accommodation is very spacious and comfortable when we compare it with that of a drainage mill.
The tower mill with a stage, the corn mill that is often seen
in old towns, generally on the town walls (wall mill) (after Krook)
The diameter of the tower mill, which is always round and made of brick, at the foot is about 30 feet. Several rooms and cabins are present, all of which - owing to the round shape of the mill - have windows giving out on the surrounding scenery; thus they form a very pleasant interior. On the ground floor are the big stable doors, two pairs facing each other, for the horse and cart, which brings the grain or takes the meal to the customers, to enter and leave the mill.
As already said, the loading and unloading of the sacks takes place with the aid of the sack hoist in the top of the mill. Square holes are cut in each floor, vertically above each other, through which the sacks are hoisted. Each hole is closed with a double-flap trap-door having a hole in the centre, for the hoisting rope to pass through. When the sacks are hoisted, they themselves push up the two flaps; when the sack has passed through, the flaps close automatically again, thus closing the opening.
The interior of an industrial windmill
The tail pole ends at the stage. It is there that the cap is turned, and instead of the anchor posts, which for other mills are planted in the ground, the anchor chain is hitched to the beams of the stage with the aid of a couple of hooks.
The BERGMOLEN or BELTMOLEN (mill built in a mound) is found in the higher regions of the Netherlands; it is a halfway house between the tower mill and the grondzeiler (ground-sail mill).
The mill itself is not particularly tall, but it stands on, or rather: in, an - artificial - mound. The base up to the first floor is built entirely into it, and the surrounding ground thus has the same function as the stage in tall mills.
Parts of the mound are dug away to give access to the large loading doors in the base, through which the horse and cart can enter, and leave the mill on the opposite side.
The interior arrangement of the bergmolen does not differ from that of corn mills in general, and this will be discussed separately below.
The PALTROKMOLEN was developed in the Zaan district, the area where wooden houses and ships were being built, where timber arrived from various parts of the world, and where sawmill yards and the timber trade were established.
Timber, which often arrives in the form of rafts, has to remain in the water for a long time before it is sawn. On this account sawmills are always situated along a water-front, and sometimes they are completely surrounded by the water, in which the logs float.
The logs and beams have to be sawn in the longitudinal direction and for this purpose they are passed through saw frames, i.e. frames in which the saw blades are tensioned and which are moved vertically up and down by the working mill.
Owing to their length the logs project considerably on either side of the mill. For this reason on both sides of the mill body some sort of roof or penthouse is provided, closed in front and open at the back. As the mill is always turned to face the wind, these wings protect the workers from the weather. They are part of the working-space, form an integral unit with the mill, and give it the characteristic appearance to which this sawmill owes its curious name and to which we have referred above.
The paltrok sawmill, front elevation (after Boorsma and Visser)
The mill itself also is entirely open at the back; it has a stage over part of its circumference and on this stage the miller can pass from one wing to the other. The floors of the wings form a continuation of the working floor in the mill and the whole is called the sawing floor, for here, in the centre of the mill, are the saw frames and on the floor are the carriers on which the beams and logs to be sawn are lashed up to be fed through the saws.
The way in which this sawing takes place will be shown later on, when the interior of the sawmills is discussed. In the ordinary windmills the brake lever as a rule projects at the back and it is there that the mill can be stopped; in sawmills the brake rope ends on the sawing floor, ready to hand, for sometimes the mill has to be stopped suddenly, when the saw makes a loud scratching noise on a nail or some other foreign object.
The mill with the wings is built entirely of wood; the cross- section of the body is rectangular rather than square, since the sides are slightly longer than the front is wide. It must be possible to turn it as a whole, along with the wings, to face the wind. It might thus be properly called a 'lower winder' - and it is the only mill of which this could be said - but this name is hardly used.
The paltrok sawmill, rear elevation
(after Boorsma and Visser)
The paltrok is supported on a circular brick wall with an oaken sill, called the winding floor. Moving on top of it are rollers, enclosed in the curb and covered by a wooden floor. The curb is connected in several places by means of radial spokes with the centre of rotation. This centre of rotation is formed by a KING POST, which rests on the heavy central pier of brickwork. Constructed round it and adapted to rotate on a heavy pin is the framework of beams on which the mill is erected, and also the heavy tail pole. This tail pole passes underneath the mill towards the back, where it projects about 10 to 13 feet beyond the curb.
The curb indeed takes part of the total weight of mill and wings, but it mainly acts as a guide during the turning. The major part of the weight is taken by the king post.
Inside the mill are several floors; from bottom to top there are the sawing floor, the frame floor, the 'empty' floor, the crank floor (where the crankshaft is to be found), and above this the top floor.
To feed the logs conveniently from the water to the sawing floor, which is some 7 feet above the water, use is made of a swivelling wooden crane mounted on one side at the end of the sawing floor. The crane rope passes towards the inside and is wound round a wooden roller, which can also be turned with a ratchet wheel mechanism through the mill gearing. Thus the log can be hoisted up by wind power, turned above the floor, and then lowered on to the carriers.
The paltrok sawmill, side elevation
(after Boorsma and Visser)
The first known sawmill was the mill called Het Juffertje (the Damsel), invented by Cornelis Cornelisz of Uitgeest; he obtained a patent on it in 1592 from the States of Holland.
In 1596 Het Juffertje was moved by water on a heavy wooden raft to Zaandam, where several improvements were made and a larger number of saws was installed in it; in this connection the name of Dirk Sybrandts is mentioned.
It was from this first sawmill that the paltrok developed about 1600, followed by sawmills of the smock-mill type. In general the span of such a smock mill is somewhat larger than that of a paltrok. Mills of this type therefore were able to saw slightly heavier logs or to work with a few more saw frames. As a rule the paltrok mills were used to saw wainscot, i.e. the oak timber that is sawn from a log which has first been cleft in two over its full length. It is then possible to saw in the direction of the medullary rays and thus to obtain the boards showing a richly grained surface, which is highly valued for the making of handsome furniture and panelling.
The body of a SAWMILL OF THE SMOCK-MILL TYPE is not erected as the customary octagon, for then there would be four upright posts in the working-space, near the carriers; a hexagon or a square is chosen. Built immediately against the mill are a couple of fixed, low sheds, extending beyond the wings forming part of a paltrok. Such a shed does not include a crane, but ends with a slipway in the water, so that the beams and logs can be dragged along it by wind power from the water and towards the saws.
The internal brake rope and other equipment are similar to those of the paltrok and will be referred to later on.
An attractive specimen of the smock-mill type can be seen as you travel from The Hague to Amsterdam; it is de Herder (the Shepherd), just to the north of Leiden on the Haarlemmertrekvaart.
Finally a few smaller sawmills exist: small smock mills and wip mills (with a stage). They were used for lighter work and in later years were sometimes equipped with circular saws.
The smallest sawmill is the lattenzagertje, a wip mill on the roof of a shed, where double laths and single laths are made.
Sawmill - smock-mill type - with sawing floor and timber stores
(front and side elevations)
Besides the sawmills there are also industrial mills of several other kinds, but to outward appearance all these mills, called after the product they delivered, belong to one of the types discussed above.
Paper mills included sheds which were exceptionally long (for the paper to be dried in), while there were oil mills with stores along the water-front and a hoisting crane for loading and unloading the barrels, but you will not be able to recognize their function from a distance; nor is it possible to tell whether the small wip mill on the roof of a shed was a pepper mill, a dye mill, or a mustard mill.
The only difference between all these industrial mills consists in the interior equipment.
The corn mills and mustard mills operated with stones rotating horizontally. In the oil and trass mills on the other hand the stones rolled on their edges in a kollergang or circular trough; the same applied to the cement mills, the shell-sand, white-lead, chalk, dye, starching-blue, cocoa, tan, and spice mills.
Oil mills and snuff mills work with stamps, in addition to the set of stones
also required. But all these mills as to their appearance can be traced back to
one of the types discussed above.
Wherever there were many windmills close together, such as in the Zaan district, practically every mill had its own name; in this way people knew exactly which mill was being spoken of. Besides, isolated mills too had often been given a name of their own. This stresses plainly the fact that a mill used to be looked upon as an individual, just like a ship.
Curious names are sometimes met with, names connected with certain peculiar circumstances, with the history of the mill or of one of its owners; the memory of this is thus kept alive for later generations. In many windmills one can find a foundation stone or a stone in the facade with an appropriate epigram or rhyme, which before he enters tells the visitor something about a past full of tradition. The millers and their descendants were greatly attached to their mills, which sometimes descended from father to son for many generations.
THE IMPORTANT EXTERIOR FEATURES OF A WINDMILL
The reader has by now learned to distinguish the different types of windmills and will be able to recognize them from a distance.
We shall now look a little more closely at the various important parts which at once strike us on the outside of a windmill.
The principal components of a windmill are of course the SAILS.
Indeed, it is the sails which transmit the wind power to all those parts which together form the windmill. Without sails a mill is a mill no more; sails are essential to it. It is obvious that the shape and the construction of the sails are of primary importance, for they determine the proportion of the energy which can be transmitted from the wind to the mill. It is the same thing as with a sailing-vessel, where the shape, position, and size of the sail determine in the first place the propulsion and the speed of the vessel. This is not the only point on which an obvious analogy exists between windmills and sailing-vessels, both being wind-driven mechanisms.
Just as the sail is spread out as a wing-shaped surface behind the mast on a vessel, so behind the stock of a windmill sail there is a surface slightly inclined to the common plane, consisting in this case of a sail-cloth covering the frame. This frame is a system of bars mortised into the stock and connected together with laths or uplongs. The bars in the transverse direction project slightly through the stock and are connected in the longitudinal direction by the uplongs. Attached to the stock are the leading boards, a set of boards which may be compared to some extent to a foresail before the mast. The wind, blowing on the sails, gives a sideways force component which makes the sails turn.
The sails of a windmill in many respects resemble the wings of a bird. If we examine which birds are the fastest fliers, we find these to be birds with long, pointed, relatively flat wings, such as swallows, gulls, and many others. Short and blunt, bulging wings belong to the rather poor fliers, such as sparrows and finches, and to the very clumsy fliers, such as chickens and the like.
Now how did the sails of yachts develop? From the bulging sails of the Old Dutch round and flat-bottomed vessels, such as boyers and barges (at first even with the primitive spritsail), yachts gradually became equipped with flatter and taller riggings with large, later very upright gaffs, the houary rigging, and from the early twentieth century, as a consistent improvement, Bermudian rigging has been used. A modern yacht is rigged with tall, pointed sails.
Entirely on the same lines we find that the most primitive windmills, as we know them from the region of the Near East and around the Mediterranean, had sails which were short and bulging. Later on, sails grew longer, at first with a sail-cloth projecting both in front of and behind the stock:
compare the square-rigged sea-going vessel, so familiar to us from illustrations, but now hardly ever found on the oceans unfortunately. It seems that the renowned Leeghwater, in the first half of the seventeenth century, was the first to suggest that it would be better to replace this sail by one entirely behind the stock. It had happened that when the storm changed its direction, the gusts began to blow on the back of the sails, causing them to turn in the opposite direction. In such a case the brake on the wind shaft has no effect, for instead of contracting on the brake wheel, it will be loosened through the reversal of the direction of rotation, so that the sails will turn faster and faster. This may cause them to break or the bearing to run hot, finally resulting in the mill being set on fire. Such an unfortunate event seems to have induced Leeghwater to introduce the sails in the form in which we know them to this day. The trouble of the flapping of the sail-cloths as they pass the mill body was also much reduced.
Types of sail:
A. Oldest type, double-sided (about 1600)
B. Normal old-fashioned Dutch type (one leading board taken away)
C. Shuttered type, with air brake
D. Shuttered type, with sky scraper
The sail is a wing-shaped surface, integral with the stock and placed on its driving side. As you will no doubt have gathered, the stock is the long timber which is mortised through the poll end and tapers towards its ends. The stock may have a length of as much as 75 to 95 feet.
Formerly the stocks were always made of pitch-pine, but in the second half of the nineteenth century iron stocks came to be used with increasing frequency.
The plane of the sail has a slight twist. On the side of the shaft the first bar is mortised into the stock at an angle of about fifteen degrees, the last bar at an angle which is much smaller or almost zero (relative to the plane of rotation of the sails). The reason of this is as follows.
Any sailing-man knows that when a ship gathers speed with a given force of the wind and sailing direction, the sheets have to be hauled upon, the sails have to be tightened. This is because the resultant of the wind and the component due to the speed of the ship comes in more forward. In the case of the sails of a windmill, when revolving, the part near the shaft has a relatively low speed, but the speed with which the stock cleaves the air becomes greater for each point that is further away from the shaft. The speed at the tip of the sail accordingly is many times greater than at points nearer to the shaft.
Consequently the sail will have at the tip a much smaller angle than nearer to the shaft. Our ancestors knew this quite well from experience, although theoretically they may not have been able to fathom this problem. Thus the sails had developed in a form which could not be improved upon very much during the past few centuries and which therefore was not modified or improved in any way.
Until - in the early years of the twentieth century - technology began to concern itself with aviation!
Before 1910 the various pioneers surprised us with their attempts to rise in the air like birds and to cover a certain distance in flight. The illustrations show that according to our present-day notions these small planes were primitively constructed and made a more or less clumsy impression.
However, the interest in aerodynamical problems had been aroused and was stimulated enormously. Experiments in wind tunnels were conducted, all sorts of aerodynamical profiles and constructions were tested, and everything was put on a more scientific basis. From about 1910 junior Delft graduates began to specialize in this field. Yacht-sailing also was studied from the scientific point of view: in 1925 appeared the well-known work by Manfred Curry on the aerodynamical principles of sailing, which on the one hand was the result and on the other hand the precursor of a somewhat revolutionary change in current conceptions about this.
In Germany the engineer K. Bilau for a considerable time had been studying aerodynamical problems, including that of the effect of the wind on the sails of a windmill. His merit lay primarily in the theoretical sphere. He hit upon the idea of giving the sails of a windmill a solid profile, without any framework and sail-cloths, and to provide them with air brakes.
In our youth the fine, short casting-angles of to-day did not yet exist; we carried the long bamboo angling rods across our shoulders. None of us will have failed to observe what great force was required to move even so thin a rod at all rapidly through the air. This struck us as a strange thing, and it goes to show what enormous resistance has to be overcome when a thick, square beam - for after all that is what a stock amounts to - is to turn rapidly through the air.
The millwright A. J. DEKKER was among the first to recognize this difficulty and to meet it in a very simple way. He did so by lining the stock with sheet metal passing round the leading part of the sail and tapering towards the back on both sides, so as to meet the framework. Thus the whole sail is given an aerodynamically improved shape, resembling the profile of the wing of an aircraft, now so familiar to us. To our view, at the present day, when even prams and fountain pens are 'streamlined', there is nothing extraordinary in this, but in the twenties the principle was regarded as rather revolutionary.
The improvements in the sails suggested by the millwright VAN BUSSEL, of Weert, were based on similar applications.
TEN HAVE, the millwright of Vorden, and VAN RIET, of Goes, fitted sails with wooden boards instead of sail-cloths; these wooden boards are adapted to pivot about an axis parallel to the stock. These sails accordingly are self-reefing under the influence of centrifugal weights. It is possible to influence the position of the boards also at will at the tail by means of a transmission mechanism, even to such an extent that the boards will act as a brake, so that one can stop the sails in a 'noiseless' way before putting on the brake.
Apart from sails with sail-cloths and the later sails with a solid profile, there are the sails with hinged shutters like those of a venetian blind, already in use in England since 1772, where they were called 'spring sails'.
The surface of such a sail consists of interconnected shutters, mounted at right angles to the stock and adapted to pivot about their own axes against spring action. These sails therefore are self-reefing and present the great advantage that the miller does not have to set or reef them, which involves a considerable saving of work. In ordinary circumstances the shutters form one continuous surface, which, like the 'normal' sail, is somewhat twisted. When the wind gathers strength, the shutters are opened a little by the pressure, thus spilling the wind. This gives rise to an automatic adjustment, so that - at least theoretically - the mill will perform a more or less constant number of revolutions in a light as well as a stronger wind.
Shutter-sails were very popular in England and modifications of them are found in Groningen Province, Germany, and Denmark. Yet it seems as if their very obvious advantages do not quite outweigh the drawbacks of this automatic system; in other parts of the Netherlands, apart from Groningen and Friesland, they are scarcely found.
The 'patent sail' was invented in England in 1807 by Sir WILLIAM CUBITT. In this, all the shutters of all the sails were connected by a spider coupling in front of the poll end. This was fastened to a rod which passed right through a bore along the wind shaft, which was controlled at the tail by adding weights on a chain attached to a lever.
Air brakes were first made by CATCHPOLE in England in 1860. They consisted of two longitudinal shutters in the leading edge of the tip of a 'patent sail'. When the sails turn too fast, the air brakes turn outwards, disturb the proper profile, and consequently act as powerful and very smoothly operating brakes, so that the racing of the mill is prevented.
There are shutter-sails of more recent design working in combination with an air brake (millwright BREMER, of Adorp), so that the shutters and air brake are not only controlled by the centrifugal weights fitted on the sails, but at will also at the tail.
In general it may be said that outwardly the shutter-sails are not so handsome as the ordinary sails, whose latticework, when seen from afar, stands out beautifully like a gossamer spider's web against the sky.
Manfred Curry has also drawn special attention to the fact that the mainsail of a yacht is pulled by the incomplete vacuum on the lee-side rather than thrust on the windward side. Further, that the formation of this extremely important incomplete vacuum behind the mast is greatly promoted by the slot effect due to the presence of a foresail. The influence of the foresail on the speed of the vessel is disproportionately greater than corresponds to the increase of sail area which it involves.
This slot effect was applied by Ir. FAUEL to the sails of a windmill. The leading board is set in such a way that a slot is formed between this board and the sail itself; these improved sails as a rule are called 'jib-sails'. The consequence of the slot effect is that the sails develop a much greater pull. In particular in a light wind this is quite evident: the mill will work in the slightest breath of wind. On the other hand the sails must not turn too fast; this has several technical disadvantages, and as a rule therefore an air brake is fitted in the leading board and is opened by a centrifugal weight via a system of cranks and levers when the speed becomes too great.
Improvements in windmill sails according to the various systems in the course of the years have been an important factor in the struggle for survival of the windmills. In a good many cases windmills have been preserved in working order because of such improvements.
The plane in which the sails rotate is not exactly vertical, as one would expect at first sight, since the wind brushes horizontally over the earth's surface. It was, however, found empirically at a very early date that it presented certain advantages to give the plane of the sails a slightly inclined position and that the effect of the wind was thus greater.
The curved lines of air flow (figures at the left give the wind velocity at different heights above the ground)
Our ancestors probably did not bother about the theoretical explanation of this. The reason is that the air flow, brushing across the land, will meet with resistance from the ground, the buildings on it, and the trees, so that the lower strata are arrested more than are the higher strata. Later measurements of the wind have shown that at a level of 43 feet the velocity of the wind is about 10 per cent greater than at 20 feet above ground-level. Consequently the lines of air flow tend to curve slightly downwards. The wind therefore is 'caught' better when the plane of the sails is inclined a little backwards.
The plane of the sails also has to be inclined - and this is perhaps the original reason - because the sails must be able to move past the mill body. For reasons of stability the body is considerably broader at the base than at the top, and without such an inclined position of the sails the shaft would have to project exceptionally far beyond the cap.
The wind shaft, which is of course at right angles to the plane of the sails, thus also has an inclined position in the cap, reckoned from the front to the rear. Its rear end is supported in bearings, which are secured on a heavy wooden structure and thus prevent the shaft from slipping backwards.
It need hardly be said that in smock mills the movable CAP forms the top of the mill body. It is as it were the bonnet on the head of the mill. The cap is high in front and low at the back.
The heavy wind shaft, which is hidden in the cap, is slightly inclined from front to rear. In front its end projects through the cap; the two stocks are mortised into it. The straight front wall of the cap is extended in the downward direction beneath the poll end, i.e. the part of the shaft projecting in front from the mill, in the form of a wooden board which affords protection from rain and which is usually beautifully ornamented. This is the baard (beard) of the mill, the graceful part which was eminently suited for the application of a name, dates, and symbolical representations; it gives a personal note to the mill and serves as a decoration. Quite often handsome carvings are found, and the beard is usually painted in bright colours: green, red, white, gilt. It is the counterpart of the decorations that used to be made on the stems of the Old Dutch ships and which impart such a gay note to them.
Baard (beard or date board)
On a great many windmills beautiful beards are still to be seen and in museums several samples can be admired, originating from mills that have long disappeared. For obvious reasons millers used to vie with each other in having their mills fitted with a fine, skilfully carved beard, the outward sign of prosperity. The beard is the striking part of a windmill, by which it is distinguished from its fellows. A fine piece of hard and durable timber was generally chosen for it.
The end of the wind shaft, projecting in front from the cap above the beard, is also painted in bright colours and decorated with a star, which enlivens the whole and as an ornament harmonizes with the bright-coloured beard.
The cap itself is covered with wooden boarding or thatched; the latter is far and away the most beautiful covering.
The cap of the polder mill, South-Holland type
Front elevation with poll end and beard
The BRAKE HANDLE projects at the back of the cap; at its end is fastened a long rope, which hangs down almost to the tail. By means of this BRAKE ROPE the brake lever is pulled, so as to put the BRAKE on or take it off, as desired.
The cap of the polder mill, South-Holland type
Rear elevation with the weather boards and the brake handle
In the case of wip mills the upright makelaar (finial) is found at the back of the cap, often finely carved and sometimes carrying a wind vane on the top. In front the underside of the body of a wip mill is often delicately curved; in the middle of the breast there is a borstnaald (prick post), which in turn ends in a finial in the form of a drop-shaped knob, ball, acorn, or the like at the bottom.
The STAGE is naturally found only on the so-called stellingmolens (tower mills with a stage). These are the mills which, in order to get a good wind, have to tower above the surrounding buildings of the town or above the trees in rural districts. The great height of these very tall corn mills is utilized at the same time to accommodate a number of floors, on which are performed the various operations which have been discussed above.
To support the stage, a large number of horizontal tie beams project radially from the tower; their ends are secured to braces extending obliquely downwards, their lower ends likewise supported in the tower. Horizontal tie beams carry a platform of boards, and round the platform is a fence, which forms a handrail for the stage.
The TAIL. Just as many caps of peasant women used to have a 'tail', one might imagine the cap of a windmill extended with what is called the 'tail' of the mill. This is the system of poles which extend downwards at the back of the mill and meet more or less at one point. At that point is also found the WINDING GEAR: a capstan wheel, sometimes with a platform.
Passing through the front part of the cap is a transverse beam which projects some distance beyond the cap on either side. From the ends of this FRONT TIE BEAM two other beams extend downwards: the LONG BRACES. At the rear a shorter beam passes through the cap: the REAR TIE BEAM, from whose ends again two beams extend downwards: the SHORT BRACES. Finally in the middle of the rear of the cap there is the heavy TAIL POLE, also extending from the top downwards.
Tail and winding mechanism of a stone towermill
Both the long and the short braces are firmly joined at the bottom to the tail pole so as to form one unit with it, and this whole system forms the tail of the mill. The tail thus has the cap firmly in its grip, and when the tail is turned round the mill, the cap is turned round as well.
All this applies to the corn mills of the smock-mill type and to the drainage mills that are found in South Holland. The cap of the drainage mills of the smock-mill type in North Holland is turned round inside the top of the mill; these mills are the so-called inner winders. They lack the characteristic tail.
The turning of the cap by means of the tail takes place on the ground, or on the stage in the case of tower mills with a stage, with the aid of the CAPSTAN WHEEL, i.e. the big wheel with a number of spokes serving as handles. The turning is necessary in order to make the sails face the wind squarely, from whatever direction it blows. The capstan has a drum round which a chain is wound. One end of the chain is hitched to one of the ANCHOR POSTS, and when the capstan wheel is turned, the tail moves round as the chain is wound up. The wheel can be fixed in any desired position about one of the spokes with the aid of a fixed end of chain with an eye.
The chain can be shifted each time from one anchor post to the next and be hitched to it, after which the same operations are, if necessary, repeated.
The wheel that turns the cap and sails to face the wind
Corn mill (Groningen type) with automatic winding by means of a fantail on
the roof of the cap.
One lever for the brake, one lever for striking the shutters
The anchor posts are sturdy and heavy posts which are sunk fairly deep into the ground, from which their round heads project a short distance. They have more or less the same function as mooring posts for mooring ships in the water or near the water-front, and they look rather like them.
As a rule twelve of these posts, and sometimes more, are grouped at regular intervals round the mill. Their heads are finished in a simple and neat manner, and of course are properly painted, usually white, so that they are easily visible, even in the dark, and one does not run the risk of stumbling over them.
The capstan wheel is also painted in gay and striking colours, and thus enhances the graceful appearance of the mill. A star painted on the end of the axle provides a pleasant note.
When we say that the wheel has to be turned to wind the mill, this should not be imagined to be easy going. Winding is a heavy job, in spite of the great length of the spokes of the wheel. As a rule the miller will not turn the wheel by hand alone, but he will simply step on to the spokes, forcing them down by his own weight: he treads the capstan wheel as in a treadmill.
Sometimes a fantail was mounted on the cap of the mill for turning the mill automatically into the wind through gearing and a rack round the top of the tower. This automatic winding device never became very popular in the Netherlands; it was only in the province of Groningen that some mills were equipped with it.
A more modern form of automatic winding has been designed for windmills generating electricity; this will be discussed in the relative chapter.
We have now described all the exterior features of the windmill. But in addition to these a good many other things associated with the windmill are to be seen in the near vicinity, thus forming an attractive complex.
The corn mill with the yard, the living quarters of the miller and his family, the drive with the entrance gate, the stores and other annexes, all these together form a small world apart.
By the side of the drainage mills we see, in the immediate neighbourhood, the simple 'summer house' of the miller; near the mill there are the scoop wheel or the Archimedean screw with the automatic sluice door, the head race which feeds the water to be pumped, and the tail race which discharges it.
Floating waterplants, duck-weed, and bits of wood drawn in with the polder water are held back by the barred gate. Alongside this gate is the plank bridge which enables the miller regularly to remove the dirt and thus to keep the gate clean.
Usually the owner of a drainage mill is also a keen fisherman, and the drying hoop-nets and other nets on the stakes, in the midst of the polder landscape suffused with light, with its water scenery, its aquatic flora, its flying birds, and the inevitable goat on its tether in the yard, present a picture of rural peacefulness and beauty. A sluice with some water seeping through the old wooden doors, the barking dog that comes to meet the visitor, these furnish the musical accompaniment to the pastoral picture which has such a beneficial effect on the hurried townsman.
In the base of the mill the windows with the small panes, the racks with the scoured clogs and on one of the numerous gates and rails the rapidly whirring toy windmill: these complete the charming scene.
THE INTERIOR OF A WINDMILL
You have by now learned to tell the different types of mill apart from a distance and have inspected their exterior features at close quarters.
You will doubtless have realized the effect of tranquillity, self-assurance, power - and splendour - of a windmill on its surroundings. The mills will have fascinated you so much that you will also wish to learn more about the mysterious interior equipment.
Have you ever entered a working corn mill? You should really do so, for you will be delighted with the romantic atmosphere created by the whirring and vibrating, the rumbling, the creaking and groaning of the timber; all this is to be heard in the dust-covered interior of the mill, which does its work though one cannot really see whence it gets the power for it. It seems to generate this power of itself, for at first sight one can hardly imagine that the noiseless breeze passing so imperceptibly over the land does all this.
It is the same thing as with a sailing-vessel (for that matter, there are many points of resemblance!), in which we experience the beneficial effect of gliding silently, without any engine noise, through canals and lakes, at one with nature around us, accompanied only by a solitary bird uttering its cry.
As the sailing-vessel is to the puffing cargo steamer, so is the working windmill to a factory interior.
It is now time to learn exactly what this mechanism looks like.
We have already seen that in the top of the mill's cap is mounted the wind shaft, slightly inclined from front to rear; in front the shaft is supported in the neck bearing, which in turn rests on the breast beam, a strong beam forming a part of the cap structure. The tail of the shaft is supported in the tail bearing resting on the inner tail beam; and at the end of the shaft is the thrust flange which takes the thrust on the shaft and prevents it slipping backwards.
Wind shafts used to be of wood and very heavy; in the poll end there were two large square openings, at right angles to each other. The stocks were passed through these openings and were firmly secured with the aid of wooden wedges. The stock nearest to the mill body is the 'inner stock', the other is the 'outer stock'. More than a hundred years ago the wooden shafts began to be ousted by iron ones. In that case the poll end is a casting, provided in the same way with two large square openings for the stocks to pass through.
Mounted on the wind shaft is the brake wheel, a wheel with a large number of cogs. The rim of this wheel is of heavy construction and is surrounded by a ring of heavy wooden blocks which are kept together by means of an iron band.
This ring of brake blocks constitutes the BRAKE, by means of which the wind shaft can be braked and stopped. To achieve this, one merely has to contract the band with brake blocks about the wheel.
This problem was formerly solved in an ingenious way. When we look at the figure, we find the brake catch, a flat iron having the form of a scimitar and adapted to swing about a point of suspension.
The principle of the method of operating the brake.
When the brake rope is pulled, the brake catch swings from right to left, so
that - in the meantime - the brake lever can be lowered,
the brake clasps the brake wheel, and the mill stops.
A pull at the brake rope causes the brake lever to rise and thus, by means of the pin in the slot of the catch, makes the latter move to the left. During this movement the brake lever is quickly lowered and by its own heavy weight contracts the brake band on to the wheel.
If the brake is to be taken off, one merely has to pull the brake rope slowly; the brake lever is then slowly raised and the pin moves upwards along the catch, past the slot. When the lever is then slowly lowered, the pin will automatically drop back into the slot of the catch, thus taking up its position at rest, so that the brake lever is fixed in its highest position and the brake band remains clear of the rim of the brake wheel.
Now that we are up in the cap, we can see how the cap is supported on rollers which make it possible for the cap to be turned. The rollers, placed within two concentric rings, remain equally spaced; they are all directed radially towards the centre of the mill and run on tracks above and below them. In a brick tower mill the curb, supporting the lower roller track, rests on the brickwork and in a wooden mill on the upper sill, i.e. the beams connecting the upper ends of the wooden corner posts of the mill body. The upper roller track is fixed to the cap circle and the whole is enclosed by a circular wooden band.
The large brake wheel drives a smaller gear wheel, the wallower (cogs in a flange or staves between two disk-shaped flanges), which is mounted on the upright shaft and causes it to turn.
In the drainage mills we found the rotary motion of the wind shaft to be transmitted below to the shaft of the scoop wheel or of the Archimedean screw. In corn mills the upright shaft on the stone floor carries a large spur wheel, which drives the smaller stone nuts, of which there are two, three, or sometimes even four.
Between the top floor and the stone floor is the bin floor; this is the floor where the SACK HOIST is to be found.
The sack hoist consists of a drum with a gear wheel, driven by a separate wheel on the upright shaft. These gear wheels can be made to mesh or be disengaged as desired. Thus it is possible to drive the drum at will by the power of the mill and to hoist the sacks of grain from below with the aid of the rope wound round the drum.
The actual grinding of the grain takes place between two big MILLSTONES, which are enclosed in a wooden casing. The contact surfaces of the stones are provided with spiral furrows. The lowermost stone, the BEDSTONE, is stationary and the uppermost stone, the RUNNER STONE, revolves above it. The runner stone has a hole in the centre, the eye. A bin, mounted on a floor above it, feeds a hopper, and from the hopper the grain falls into the shoe and thence into the eye of the runner stone. It is ground between the stones, moves through the furrows to the outer edge, and passes as meal through the casing.
A wooden spout communicating with the casing conveys the meal to the meal floor beneath, where it is collected underneath the discharge opening in sacks, ready for transport.
These wooden spouts can be shut off at the lower end by means of wooden gates, which can be raised.
The bedstone is kept in place on the stone floor by means of wooden clamps. The quant has to drive the runner stone and thus has to be firmly anchored in it. This is achieved by means of a rynd, i.e. a cast-iron cross with equal arms, having in the centre a square opening for the cock-head of the spindle to pass through. The four arms are let into the stone and cemented into it.
Tentering: the adjustment of the gap between runner stone and
bedstone is shown in the diagram
It is this part of the mill which is very familiar in heraldry in numerous escutcheons of families which were associated in one way or another with a windmill. Several variations of it exist, generally in a form with slightly concave arms.
The mill rynd in heraldry
In a strong wind the power of the mill increases, it will be able to grind larger quantities than in a slack breeze. In order to make use of this greater capacity, the gap between the stones has been made adjustable, so that it is possible, dependent on the available power, to admit larger or smaller amounts of grain between the stones, thus regulating the load and increasing the output.
This adjustment (tentering) was carried out in a very simple, but ingenious way. The runner stone rests on the bridge tree via an iron 'stone spindle' passing through the bedstone. One end of the bridge tree is hinged to the wooden framework of the mill and the other end is held up by means of a suspension system in such a way that the weight of the millstone is balanced as much as possible by a counterweight. The force required to move the stone up or down is thus only slight. One merely has to raise or lower the cord a little if one wants to raise or lower the runner stone.
Later on, an automatic centrifugal governor came to be used for this purpose.
The drive of the stones is also turned to account to vibrate the shoe, so that the flow of grain cannot be interrupted, but will continue uniformly.
The stones have a diameter of some five feet and a thickness of twelve inches. They used to come from the volcanic regions of Germany and the quartz beds of France; owing to their constitution they were porous and consequently had good cutting properties. For some purposes, millstone grit was sometimes used and later on composition stones.
The sharpening of the furrows is called DRESSING and this is a highly skilled job; the grade of the meal largely depends on it. When the stones have been used for some time, they become dulled and have to be dressed. For this, the runner stone has to be raised, which is a heavy job in the cramped space available for it. The dressing itself takes place by the light of an oil lamp hanging over the stone, for the poor daylight entering through the small windows of the mill is on the one hand too scanty to allow proper work and on the other hand causes cast shadows, which would make dressing even more difficult. The shutters are therefore closed.
For the dressing operation use is made of special hammers, called bills, drawn out to a chisel point at each end. It is self-evident that dressing was a difficult and lengthy job and formed an important event in daily mill routine; all that time no grain could be ground. By means of the position of the sails the miller would inform everybody in the neighbourhood that the stones had been raised, so that for the time being no grain could be accepted for grinding.
The governor, which automatically adjusts the distance
between bedstone and runner stone
In barley mills and rice-hulling mils, HULLING STONES were used instead of millstones. They were somewhat larger than the common millstones and the casings were also constructed a little differently. The barley or rice did not have to be ground but was hulled, i.e. the thin outer covering of the grains had to be removed. The stones were usually gritstones and the runner stone had only a few deep and wide furrows, through which the grains were flung out as the stone revolved, without being ground between the stones. The wall of the casing was lined on the inside with tin sheeting, in which holes had been beaten in such a way that the sharp points were turned inwards, thus forming a cylindrical grater. The grains were flung against it and rubbed by the circular edge of the stones, freed from their hulls or shells, and smoothed. Whilst barley, used to be a favourite national food, in the early part of the nineteenth century it was replaced more and more by imported rice; this rice too was treated in the hulling mills.
For the grains to be flung out it is necessary that hulling stones should revolve faster than millstones; it was a heavy job and hulling mils were powerful mills, which required a strong wind for operation. It was possible to use a higher or a lower gear in the mill, as desired, according as the speed was low or high.
Instead of a sack hoist such mills often contained an elevator buckets on an endless belt - which lifted the barley and regularly poured it into the hoppers.
For all the additional work a third spindle was present, taking its drive from the upright shaft via a separate gear wheel.
Besides mills for grinding and hulling there were also OIL MILLS for pressing oil from seeds, MUSTARD MILLS, and the like, as well as mills in which all sorts of coarse and hard materials were ground fine. The last category includes the mills which made dyewood into DYE, the CHALK MILLS, the TRASS MILLS, etc. This grinding operation took place in a kollergang (an edge mill), i.e. a couple of runner stones rolling on their edges in a stone pan.
The principle of the kollergang or edge mill,
two edge runner stones rolling on the pan, with wooden guides
The stones are mounted on a shaft, which is driven by the stone spindle from the spur wheel. There is an outer and an inner stone, the latter running about 8 inches closer to the spindle, so that a broad track is covered by the two stones. The seed is pulverized between the heavy rolling stones and the pan underneath. A couple of curved wooden guides following the motion of the stones ensures that the seed rolled out under the stones is promptly returned to the track of the runners.
When it has been pulverized sufficiently, the meal is brushed together and poured into a receptacle underneath through a gate which can be opened. We shall discuss the further treatment of these oil-seeds in oil mills later on.
The most important parts of the interior equipment of a TIMBER SAWMILL are of course the SAW FRAMES, i.e. the wooden frames with saw blades, which are reciprocated by the movement of the mill.
Crankshaft and saw frames in a sawmill (after Krook)
In the upper part of the mill there is a horizontal crankshaft, which is driven by means of the gear wheel mounted on it, the crank wheel. The rotation of the wind shaft is transmitted via brake wheel and wallower to the upright shaft, and further downwards the upright shaft carries a crown wheel, which in turn drives the crank wheel.
When three cranks are present, they are placed at 120o to each other, so as to ensure as uniform a distribution of forces as possible.
Vertically suspended from each of the cranks is a connecting rod, the lower end of which is fastened to the saw frame. To the left and the right of each crank the crankshaft is supported in a bearing block in which the shaft is able to rotate while at the same time being firmly held in it.
As a rule there is one large saw frame, about 4 feet broad and 6 feet high, located between the front of the mill and the upright shaft, and two smaller saw frames at the back. Mills of the paltrok type usually have two saw frames, one on each side of the upright shaft; for balancing purposes the third crank is then used to move up and down a dummy frame, which has the form of a case containing weights; the latter is placed on the frame floor, above the saw frames.
Occasionally there are four saw frames in a sawmill, two in front and two at the back.
A saw frame is a strong wooden frame consisting of two uprights which are connected at the top and the bottom by the heavy tensioning beams. The saw blades are tensioned between them. Above the upper tensioning beam there is another connection between the uprights, the cross-head; to the latter the connecting rod is fastened. Because the upper end of the connecting rod performs a rotary motion, it is necessary that the point of application of the connecting rod on the saw frame should be able to make a small pivoting movement. This is made possible by the cross-head; it has been let into the uprights by means of pins.
The whole saw frame is moved regularly up and down by the cranks via the connecting rods. The lower tensioning beam in its highest position always remains some four inches beneath the sawing floor.
The big frames serve to cut up the thick baulks and logs; this is done in smock mills, which are stronger than mills of the paltrok type. The latter saw wainscot, the smock mills saw baulks.
The baulks, logs, and boards to be sawn are lashed up on a carrier moving over the sawing floor of the mill, each saw frame having its own carrier. Sometimes a set of rollers is found instead of a carrier.
The sides of the saw frames slide in grooves of lignum vitae, so that they are forced to reciprocate vertically. At the downward stroke the saw makes its cut and with the upstroke the carrier with the timber to be sawn has to be advanced slightly. This movement is performed with the aid of the TIMBER FEED. This consists of a shaft, on which are mounted a small pinion and a large toothed wheel, the ratchet wheel; the latter has a great many oblique teeth. The teeth of the pinion mesh with those of the rack, i.e. a long and straight iron with a series of teeth on it, which in the central part of the carrier is integral with it.
Simultaneously with the motion of the saw frame a reciprocating lever moves the end of an arm up and down, so that with each stroke the ratchet wheel is advanced by one or two teeth and the carrier correspondingly is advanced a little with every upstroke.
On the frame floor there is a separate similar ratchet wheel, which provides in a similar way for the rotation of a wooden roller round which the crane rope or a towing rope has been wound. The crane rope passes over the pulley in the crane outside, and in this way it is possible in mills of the paltrok type to hoist the logs and baulks from the water by wind power. Similarly in the smock mills the baulks are dragged from the water with the aid of the towing rope and along the slipway on to the sawing floor, so that they may be deposited and fixed on the carrier. A ratchet mechanism again ensures that the roller cannot rotate backwards of its own accord.
The timber feed of a sawmill (after Boorsma)
We will now return once more to the OIL MILLS, the edge runner stones of which have already been discussed.
The task of these mills was to press oil from the different kinds of seed: coleseed, linseed, rapeseed, and sometimes also hempseed. These oils were indispensable to daily life at that time, and they served for the most varied purposes: for human consumption, for technical purposes, for lighting (rapeseed oil for the old-fashioned oil lamps), etc.
In the oil mill the seed was first crushed under iron cylinders and then ground and rubbed in the edge mill. After having been heated, if necessary, it was pressed by means of rams and pulverized by stamps.
A single-working mill had, in addition to the couple of stones, one set of rams and three stamps. Most mills, however, were of the so-called double-working type: two sets of rams and six stamps. There were even a few mills equipped with two clouble mechanisms. All these RAMS and STAMPS, like the edge runner stones, are driven by a system of gear wheels from the main shaft of the mill.
Method of driving rams and stamps of a double-working oil mill.
Above left: the method of lifting the rams and stamps
By the side of the edge runner stones there was a fire-place, built of fire-bricks; this was fired with peat and served to heat the ground seed, the meal, in advance. Opposite the fire-place was the pressing block for the first operation.
The heated meal was put in a woollen bag, which was packed in a horsehair cover in the form of a kind of mat. During the pressing operation the oil was able to escape through the numerous pores of the fabric.
The package was put in the cavity of the first pressing block intended for it and locked in it with the aid of spacing blocks. These included two wooden wedges, one of which was inserted with the thick end up and the other with the thick end down. The former was the pressing wedge, the latter the releasing wedge. Above the block hung the two rams, the striking ram and the releasing ram.
The striking ram was then put into operation and through the numerous strokes on the pressing wedge the contents were greatly compressed in consequence of the wedge shape. This operation was not allowed to take place too quickly, for the oil had to have time to flow off through all the pores into the receptacles underneath. In view of this there were only two cams on the cam shaft for the first pressing ram.
After fifty strokes the mass had been pressed sufficiently and a few blows of the releasing ram on the releasing wedge sufficed to remove the spacing blocks, and the mass, which had become a cake, was taken from the bag. The cake then still contained some oil, but this was removed from it by the second pressing operation. For this purpose the cake was broken up and pounded in the pots underneath the stamps, and, after being re-heated, it was subjected to the same treatment again in the second pressing block.
When all the remaining oil had thus been removed, the cake, which still contained a few per cent of oil, could be removed and stored, to be sold as cattle feed.
The correct number of the strokes with the ram was checked by means of a bell, which was operated by a ratchet system after a given number of strokes had been set, and which then, amidst the deafening noise of the stamps, warned the attendant that it was time to 'release'.
An oil mill at work, with its frequent booming strokes, could be heard for miles around, and inside the mill the thumping was so terrific that people could not make themselves heard. This frequently gave rise to a special kind of deafness.
An outsider cannot understand how the people living in the neighbourhood could endure such a noise going on night and day, but it seems they got used to it in time and did not hear it any more. They even awoke at night when for some reason or another the mill stopped, and then they were unable to get to sleep again because of 'the unpleasant noise' of the unusual 'silence'!
The interior equipment of the various other types of industrial mills, which have been mentioned more than once, does not differ essentially from the above descriptions, and it would take us too long to discuss all these types in detail.
In the paper mills, milling and stirring mechanisms were driven by rotating shafts, in the dye mills, chalk mills, tan mills, etc., in which some material was pulverized, edge runner stones operated in the way described above. Stamps were used in fulling mills and snuff mills.
Several details have had to be left out of account, but the reader will have got some idea of the way in which the windmills could perform their widely varied task.
One thing, however, of which no description can give an idea, is the very clever way in which the various wood constructions were made by the millwrights in the old days; they bear witness to highly developed craftsmanship. The numerous small details too, so well thought-out and finished with such care, fill us with admiration of the men who with very simple tools were able to construct it all so perfectly.
Anyone interested in windmills will therefore find it worth his while to devote close attention to their interior.
TRADITION IN WINDMILLS
When we see the windmills in the landscape, we shall find that when the sails are at a standstill they are not always and everywhere in the same position. There is a reason for this, for the different POSITIONS OF THE SAILS all have their own special meaning. In this way the miller can give information of different kinds, indicate particular circumstances, and even express particular sentiments.
Formerly the miller, like the burgomaster, the notary public, and the schoolmaster, was an important figure in the rural community: everything that went on in the village attracted the attention of the miller, who moreover had plenty of opportunity to discuss all the news at length with his customers, who came to call for the meal and often had to wait some time. He used to intimate certain events by means of the position of the mill's sails, visible to all from afar, and it is small wonder that conversely the mill formed a centre of village life, for young and old.
It was quite easy to read the 'code' of the sails, even at a great distance, because from the nature of things a windmill is clearly visible from all sides, since it is often built on a natural or artificial mound and always rises above all the buildings and trees surrounding it. And for drainage mills, which are usually situated at great distances from the inhabited world, the same thing holds as for ships at sea, viz. that men like to indicate their intentions across a considerable distance with the aid of signals, sometimes combined with the use of flags.
The position of the sails accordingly speaks its own language, which is clear to all who can read it.
When looking at a mill from the front, you will find that the sails always turn counterclockwise. The origin of this is to be sought in the fact that this is the most natural direction in connection with the handling of the sails by the miller. When the miller has to reef the sails, furl them up, take them in, or set them, he starts by climbing into the sail. It stands to reason that he begins in the sail that is directed vertically downwards. He mounts the framework and - just as on board ship - has to use one hand to hold on and the other to handle the sail-cloth (the rule on board ship is: one hand for the ship and one hand for work). It is obvious that he will use his right hand for the work; this implies that he must have the stock on his righthand side in order to detach the cloth or fasten it. And thus the sail, when directed vertically downwards, having the stock to the right and the framework to the left, the sails have to turn counterclockwise.
So looking at the upper sail, you will always see it move from right to left. Now the miller expresses 'joy' by making this sail stop just before it reaches the highest (vertical) position; he then fixes the sail in the so-called 'coming' position. The upward movement which the sail can then still make is associated with joy, and this is easily remembered by everybody concerned. The position of joy announces celebrations in the mill, on account of the birth of a son or daughter, a marriage, a solemn birthday, or something of the kind. Frequently a flag is also flown from the cap of the mill or from the sail in its highest position. This presents a very gay spectacle.
When the upper sail has been fixed after having passed through the highest position, it is in the 'going' position; this is the position of mourning, indicating that the culminating point has been passed and life is going downhill. This is the position when a member of the miller's family has died or there is some other reason for mourning.
When a funeral procession in the village passes the mill, even when the person who is to be buried was not directly associated with the miller or his family the mill will still be set in the mourning position. It is decidedly a touching sight when cap and sails are turned to follow the direction taken by the procession and finally stop in the position facing the churchyard.
Joy and mourning are the most pronounced sentiments that can be read from the position of the sails. But there are also other messages which the miller conveys by means of the sails in intermediate positions, such as the request to a carpenter or a millwright to come to the mill for repairs to some component, or the information that the stones are being dressed, so that for some time to come no grain can be accepted for grinding. In the case of drainage mills the sign to start or stop pumping in connection with the level of the water of the storage basin or the water level in the polder, or with fouling of channels or ditches, is also given by means of the position of the sails; and there are more things that can be indicated in this way. Those who wish to learn more about this may be referred to other publications.
Four characteristic positions of the sails
Above left: rest for a short time during working period
Above right: rest for a longer period
Below left: 'celebration' position, with the upper sail just before the vertical
Below right:'mourning' position, with the upper sail past the vertical
(The sails turn counterclockwise)
Now that we have spoken about different positions of the sails which give expression to particular moods in the miller's family and in village life, we must not omit to mention the position of the sails in ordinary circumstances.
In summer, the drainage mills have little work to do - for though a mill can pump out much water in 24 hours, the evaporation due to the milliards of blades of grass and reeds in summer is a multiple of this - and the windmills are in the 'rest' position: the sails then form a St. Andrew's cross. This is the proper time for carrying out some additional maintenance work or giving the mill a fresh coat of paint, brightening the colours of the star on the poll end, painting the gates around and near the mill a fresh white and green.
When the sails are at an angle of 45 degrees to the vertical, this indicates that the mill will be unused for a considerable time.
A rest of short duration, i.e. in the milling season proper, when the mill is ready to commence work at any moment, as soon as the wind gets up, is shown by one pair of sails in the vertical and the other pair in the horizontal position.
WINDMILLS AND MERRY-MAKING
Frequently - especially in the Zaan district - joy used to be expressed in a more exuberant way than by the position of the sails alone, particularly when there was a wedding. The windmill on such an occasion was hung with 'finery', all sorts of simple products of folk art, small flags, cuttings in the form of hearts, letters, and other appropriate things and symbols, glistening tin-foil disks, rings, wreaths, Cupid's arrows, and even trumpeting angels. Sometimes an additional set of furled sail-cloths was laced in and out of the framework to make the whole thing as showy as possible. Those who are specially interested in this matter may study it more fully at the 'Zaans Molenmuseum' at Koog-aan-de-Zaan (a visit to this museum may be warmly recommended to all lovers of windmills!). From the point of view of folklore it is undeniably fascinating, but to be honest we can never be very enthusiastic about such a decorated windmill. It is too suggestive of a beautiful old city square or village green where a fair is being held, which as a rule completely spoils the fine characteristic features of the place. All that is beautiful there is then shouted clown altogether by the trumpery of the booths and merry-go-rounds, the noise and the rubbish attendant upon it, so that nothing is left of the pleasing atmosphere of the place.
It is somewhat similar with a decorated windmill. Owing to the cheap ornaments on and about the sails and in the framework, the handsome contours of the mill and its imposing appearance are practically lost to view, and such a mill looks more or less like a showdog in a jacket and with a forage cap on its head. In principle such an expression of popular joy is alright, but it makes a rather unnatural impression. As a display of popular rejoicing it is interesting, just like an oldfashioned fair, and on that account it is worth while to preserve it as an historical curiosity.
At the present day there are other means for giving a windmill a central place in general celebrations. What more festive spectacle can be imagined than that of a handsome wall mill floodlit at night? It is also possible to mark the contours of the sails, the body, and the railing, the windows and the door with small electric bulbs, but although this makes a pretty impression, the effect is not so natural.
Whilst formerly a decorated windmill would bear witness in a natural way to the joy felt about some special event in the miller's family circle, nowadays a mill becomes the monument which in the splendour of floodlight gives expression to the mood of rejoicing of a whole town.
In a simple way a town can thus show its attractions to its own inhabitants as well as to strangers. All too frequently it is forgotten that a windmill constitutes a graceful monument, deserving to be made the centre of interest, all this at minimum expense.
THE CAPACITY OF A WINDMILL
After the war, in 1946, the prospects for windmills were extremely gloomy. A great many of them had been damaged or destroyed by acts of war, no repairs had taken place for many years past, everything was disorganized, and confusion reigned, while there were no prospects of recovery.
It was then that the Dutch Windmill Society sounded the alarm and the idea was launched of keeping the windmills turning by making them work in combination with an electric drive to the machinery, which would at the same time make it possible to generate electricity during periods of a 'surplus' of wind.
Before reporting on this matter, however, it is of importance first to devote some attention to the technical properties of windmills in general.
What is the CAPACITY of a large polder mill?
This question has always formed a point of discussion and widely varying answers have been given to it from time to time. Nor is this very surprising. A windmill transmits the power which it derives from the wind. And this actually varies from one moment to another; hence the capacity of the windmill varies too. Moreover it also depends upon the load required.
The wind blows with a certain velocity, but this does not mean that this velocity is constant throughout. On the contrary, it will vary at any moment, and even in an air flow apparently having a constant velocity there will always be gusts and blasts which have a greater velocity. Nor is the amount of energy, accumulated in a given air flow of a given velocity, constant. It depends upon the condition of the air: barometrical height, humidity, and temperature. Any skipper will know that in the winter season the air is 'denser' than in summer and that, even if the wind has the same velocity, it will bear down on the sails more heavily.
The wind blows through the turning sails of a mill, passes on, and thus gives off only a limited part of the accumulated energy to the wind shaft. In the transmission gearing of the windmill some of the energy is lost of course, and the scoop wheel too gives less power (in the form of scooping up water) than the input that is delivered to it by the mechanism of the mill.
A small variation in the velocity of the wind already has a considerable influence on the power output of the mill, for the output is proportional to the cube of the wind speed, and consequently also to the number of revolutions of the sails as far as this number is proportional to the wind speed.
But this proportionality does not always hold good, for in a strong wind the sails have to be reefed, in order that the mill may not perform more revolutions than it can stand up to on account of its construction.
If with increasing wind speed the mill is loaded more heavily, e.g. in a corn mill by adjusting the gap of the stones and the feed of grain, the number of revolutions of the sails may remain practically the same and yet the power output will be higher.
Thus there are a great many variables, and it will be obvious that 'the capacity of a windmill' is not a constant magnitude. It stands to reason that it also varies with the size of the mills: the capacity of a windmill is proportional to the square of the length of a sail.
It is thus not surprising that many different figures have been given for the performance of a windmill and that the figures recorded will often not bear examination.
Besides, the most important point is not the power which a windmill can derive from the wind at a given moment; it is of much greater interest to know what amount of energy a particular mill is able to deliver in a given period of time.
Indeed, this is the crucial point when a windmill is to be judged in its function of draining off the polder water in a given period or of delivering the meal in a given time.
The most recent measurements are those made during the tests on the windmill at Benthuizen.
Without going into details, it became clear in the course of the years that we may establish a few main points in answer to the question with which we are here concerned. The question should therefore really be put as follows: what is the maximum power which a large octagonal windmill can derive from the wind and what is its output during a given period of time?
To answer this question, we shall first have to become familiar with a few elementary concepts.
In order to indicate the strength of the wind by the same international standard, the force of the wind has been arranged according to the Beaufort scale, in twelve different degrees of strength.
Forces 0 to 2 form the 'light breeze' of the weather forecast, the breath of air in which the leaves will rustle. The 'gentle to moderate breeze' is referred to by the numbers 3 to 4 of the scale: leaves, twigs, and small branches will move. The next in order is the 'fresh to strong breeze', forces 5 to 6; at 5, small leafy branches will make swaying movements, crested waves will form on lakes and in canals. At force 6, the 'strong breeze', big branches will move and the wind will whistle in the telegraph wires; larger waves will form, which cause foam patches, and umbrellas can be held only with difficulty.
This 'strong breeze', which is wrongly looked upon as storm and so termed by the man in the street, is followed by the real 'gale', forces 7 and 8 of the scale. At force 7, the 'moderate gale', whole trees will move, we are hampered in movement, and at force 8 twigs will break off and we have to strain against the storm. From now on it is a gale, force 8 and upwards: chimneys and roof tiles are torn off and buildings are damaged.
What wind speeds, in metres per second, correspond to these various forces?
The light breeze, of 0 to 3 metres per second, corresponds to the forces up to 3 on the Beaufort scale. The moderate breeze, forces 3 and 4, has a speed increasing from 3.5 or 4 to 7 metres per second. At forces 5 and 6, the strong breeze, speeds are 8 to 11 or 12 metres per second. The moderate gale, force 7, will have a speed of 12 to 13 and 15 metres per second, and the fresh gale, force 8, a speed of 13 to 15 metres per second and upwards. At 12 and 13 metres per second it is necessary to stop the mill.
Thus far we have spoken about the driving force of the windmill, but what about the power output?
Let us take a drainage mill with a scoop wheel. At a small number of revolutions per minute a scoop wheel requires relatively little power; this increases with the number of revolutions. Owing to its construction it can transmit only a given proportion of the power by which it is driven in the form of output. The latter is realized in raising a certain quantity of water through a certain height in a given time and is expressed in so-called water horsepower (W.H.P.).
One W.H.P. corresponds to raising 75 litres of water per second through a height of 1 metre.
With a reasonable number of r.p.m. about 50 per cent of the H.P. which the mill generates from the wind will be given off by the scoop wheel in W.H.P. Under certain circumstances the scoop wheel of an unimproved mill will be able to give off a maximum of 20 W.H.P., provided the mill and its components are in good condition. when the number of r.p.m. decreases, i.e. when the wind becomes lighter, the power output will soon become considerably lower. For the unimproved mills this begins already as soon as the wind speed decreases below 8 metres per second.
The earlier - unimproved - windmill only started to turn at a wind speed of 5 to 6 metres per second. It would then turn only very slowly, and the scoop wheel would displace hardly any water, only just enough to force open the sluice gate. As the wind increased, the mill, in 'full sail', would begin to displace water, and above 8 to 8.5 metres per second it would feel really in its element, while with the wind gathering strength it would attain full speed, say about 75 to 85 'enden' (i.e. ends), as it is called in miller's terms.
The number of 'enden' is the number of times the tip of a sail passes by per minute, i.e. four times the number of r.p.m. of the wind shaft. With this number the mill will generate about 50 H.P. from the wind. When the wind increases even further, the sails will have to be reefed, from wind speed about 10 metres per second on, and from 12 metres per second on the miller will work the mill with the sail-cloths furled. Then the wind has already gathered to a gale and it will not be long before the mill has to be stopped and anchored. The maximum number of r.p.m. which a windmill can stand up to is generally about 90 'enden', sometimes slightly more. This involves the risk of the mill running away, for the scoop wheel will then rotate at too high a speed: the water will splash to the sides and whirl round rather than being raised, for the flow of the polder water cannot keep up with it; it has hardly time to flow to the scoop wheel and the 'buckets' of the latter are not filled sufficiently. It does not give a sufficient load to the mill, and there is a risk of everything going to pieces.
In industrial mills it is usually possible with increasing speeds to increase the load somewhat and in that case the power output of the mill will be slightly greater, perhaps 60 H.P., with occasional peaks of 75 and sometimes even 90 H.P.
And now for the difference between the unimproved and the improved,version of the windmill.
An improved windmill will already turn at a wind speed of 3.5 to 4 metres per second; at 5.5 meters per second its power output will be equal to that of a normal mill at 8 metres per second. At the same wind speed an improved mill will attain to a considerably larger number of r.p.m. than a normal mill.
That is a great gain. With stronger winds the difference in effect is not so great, for the sails of an improved mill will have to be reefed sooner, a normal mill on the other hand will then still turn in full sail and the number of 'enden' of the two mills will be approximately equal.
In the course of the tests with the windmill at Benthuizen, a mill with a span of 86 feet and improved sails, it was found that (with 66 'enden') the average power output in one hour was 55 H.P., but that momentarily it was two and three times greater!
An improved windmill has two advantages: the greater power output at a given wind speed and the longer working hours; the latter is due to the fact that an improved mill can utilize the many hours of lighter wind, which are of no value for a normal windmill.
From the wind statistics of the Netherlands Meteorological Institute it appears that for a number of years there will be an average of 3,754 hours a year when the wind has a speed of less than 4 metres per second. Between 4 and 6 metres per second this figure is 1,771 hours, and wind speeds of 6 to 8 metres per second occur during 1,332 hours a year, wind speeds of 8 to 12 metres per second during 1,339 hours a year.
A normal windmill therefore can utilize no more than a total of 2,671 hours a year, but an improved mill will utilize 4,442 hours. An enormous difference indeed! And if the hours of the lightest wind in which the mill will still turn were to be included in the reckoning, the total would be greater still. However, it has to be conceded that very little water will be displaced during these hours; but the same also applies mutatis mutandis to a normal windmill.
The annual output of an improved windmill may therefore be assumed to be approximately twice as great as that of a normal windmill.
Of course even an improved windmill presents the drawback of every mill, that it cannot turn when there is little or no wind; also that the periods when there is much work to be done by the mill do not always coincide with periods of good wind.
With drainage mills this drawback was always met as best it could by the provision of extensive water storage in the polders as well as in the basins. Nowadays this drawback can be overcome in a simple way by the installation of an electric auxiliary pumping plant. This can easily be accommodated somewhere; if necessary, in the mill itself or close by. It does not spoil the appearance of the mill.
From the above the conclusion might be drawn that the improvement of the windmill might be utilized even better if it were loaded with machinery capable of absorbing a considerably greater power than normal. Up to a certain point this is true, but the question then arises whether the construction of the mill as a whole is really adapted to this. The windmill may be said to have been greatly perfected through the ages, but its construction was always based on an understanding of the forces to which it was subject. If higher demands are made in some respects, the harmonious whole will be disturbed. When a component part is broken, it can be replaced by a new one, so strong that it will break no more; but then another component will soon give way, and so on. In our opinion therefore the question can only be answered in the negative.
WINDMILLS AND ELECTRICITY
We have already referred briefly to the tests with the Benthuizen windmill. Some details may be given of them here. The tests were taken to find out in how far wind-power in a mill might be combined with an electric drive, and further whether the change-over from one kind of drive to the other would be possible in a simple manner during day-to-day operation. The technical appointments of the Benthuizen windmill were highly suitable for these tests; the only thing needed was the inclusion of an overrunning clutch.
'Tandem' operation was found to be actually feasible: in periods of absence of wind the water-raising apparatus (in this case a rotary pump) was driven by the electric motor and in periods when the wind was favourable the sails drove the water-raising apparatus and supplied any surplus of wind power in the form of electricity to the public electricity network.
The tests continued from 1948 to 1951 and furnished valuable information. Anyone who wishes to learn more about these tests is recommended to read the report delivered by the Committee and published by the Dutch Windmill Society in cooperation with the Organization T.N.O. in 1951. The result was that the mill in day-to-day operation appeared capable of generating a quantity of energy in the order of magnitude of 50,000 kWh a year.
During the tests several new aspects presented themselves, which made it desirable to call into existence a separate institute which was to study everything connected with the generation of electricity in greater detail and to put it to practical tests.
Thus in 1951 the Stichting Elektriciteitsopwekking door Windmolens (Foundation for the Generation of Electricity by Windmills) was established, which undertook to carry out different investigations and to examine the possibilities of more automatic operation. The latter includes automatic winding of the mill and adjustment of the sails. If any new inventions should be made, they might also be used to improve windmills in general.
Since its establishment this Foundation has equipped two windmills for the generation of electricity: the corn mill De Hoop (Hope) at Wervershoof (North Holland), which started trial operations in 1955, and the corn mill De Kraai (the Crow) at Achttienhoven, province of Utrecht, which started in 1958. Both mills are equipped with shutter sails and sky scrapers in the streamlined tips, so that they are reefed automatically and the mill can be stopped smoothly.
Special safety devices have been provided to prevent the mill from racing in case of a gale or of a failure of the electric supply.
There remains the great difficulty in the economic sense that the generated electricity that is supplied to the public network has only a small commercial value.
The devices that make possible electric winding and reefing are interesting, just as is the safety device in case of gales. These devices would seem to give great satisfaction and their application will be able to lighten the miller's duties considerably, so that he will have more spare time for other occupations.
The third windmill to be equipped for the generation of electricity is the mill De Traanroeier at Oudeschild, Texel.
THE PRESENT SITUATION
We may assume that around 1850 some 9,000 windmills were at work in the Netherlands, the largest number that ever existed. We know the circumstances which, in the sixteenth, seventeenth, and eighteenth centuries, caused a great many windmills to be erected; even in the nineteenth century, except perhaps the latter part of it, several mills were built. Windmills dating from 1851, 1857, and 1860 are known.
But still, 1850 formed the peak. After that time the number of mills decreased steadily, at first slowly, later on more rapidly.
After the principle of the atmospheric steam engine had been discovered by Newcomen in England in the eighteenth century, steam power was applied for driving the pumps in English coal pits. In the latter part of the same century James Watt invented the condensing low-pressure steam engine as we know it; this started a great technical advance and formed the prelude to the triumph of steam engineering.
In 1805 Richard Trevithick, a Cornishman, drove a 60 to 70-ton barge on the Severn by steam with paddles, in 1819 a ship which in addition to its sails was equipped with a steam engine as auxiliary power crossed the Ocean; in 1827 the first ship exclusively propelled by steam power crossed the Atlantic.
In 1804 the first steam locomotive was built, also by Trevithick, but before this the stationary engines had already gone through a considerable development, and in many factories in England they were used to drive the machinery.
Pumping stations for pumping the water from the coal pits, steam hammers, and other steam-driven apparatus were applied there for the most varied purposes. The reliability of steam engines had been proved and foreign buyers ordered many steam engines from English manufacturers. Apart from some incidental trials, the first pumping station to be used in the Netherlands was applied in the reclamation of the Zuidplaspolder, which had been decided upon in 1825.
Polder boards, naturally rather conservative, at first remained somewhat reserved towards the steam pumping stations. The degree of reliability was not yet high enough to them, seeing that matters of life and death, such as keeping the polders dry, were at stake. Moreover the engines called for expert attendance and coal consumption was high. Good enginemen were scarce in the rural districts and difficult to keep. All these causes tended to retard the introduction of steam engines for polder pumping stations.
The decision to reclaim the Haarlemmermeer (the big Haarlem lake) changed all this; such a large project could only be executed with the aid of steam power. Three large steam engines of 400 H.P. each were ordered from Harvey's in England and these drained the big lake from 1848 to 1852.
This started the advance of the steam engine in the Dutch polder districts, an advance which received a new impulse when the axial-flow turbine pumps became more widely used, since they were better adapted for use with the steam engines than were the scoop wheels. Thus, in the Netherlands too, steam power was steadily gaining ground. Steam locomotives pulled the trains, puffing and trailing clouds of smoke, through the country, and men were growing steamminded. The term 'steam' was gradually identified with 'speed'; even in the early years of the twentieth century the country lad used to speak of a stoomfiets (steam-bike) when he meant a motor-bike.
People began to consider themselves as being behind the times if they did not employ steam power, and for the polder boards it was becoming increasingly attractive to buy a steam plant, by means of which the water level in the polder could be controlled more effectively and quickly than by means of windmills. Thus the characteristic pumping stations arose in the polder landscape: the familiar boiler house with pointed gables and arched windows, an engine house, a coal shed, and a house for the engineman, the whole complex recognizable from afar by the tall brick chimney, puffing out black smoke when the engine was operating.
Such a pumping station in a polder made all the windmills, which for years had kept the polder dry, idle and superfluous at one stroke, sometimes four, six, or seven of them at a time. Frequently people did not even take the trouble to pull down the mills, but only demolished the upper half, putting a thatched or a tiled roof on the lower part of the mill body and thus disfiguring it to provide a cottage for an agricultural labourer. To the present day in several places these monstrous structures can be seen, hideous stumps of windmills, too ugly to look upon.
In consequence of all this, by the turn of the century no more than 2,500 windmills were left, and even after that the massacre of the faithful helpers proceeded steadily.
What applied to the polder mills in the latter half of the nineteenth century, could also be observed for the industrial windmills. Several milling industries were converted into factories, in which the work could be performed more quickly and on a larger scale by a steam engine. The original windmill was then abandoned and pulled down wholly or in part.
The early years of the twentieth century witnessed the advent of the internal combustion engine and the electric motor. The process that had taken place a number of decades earlier, owing to the development of steam power, started anew; history repeated itself. The development of electricity, which in the towns was already well on its way, took possession of the rural districts; pumping stations became a welcome outlet for electricity in the villages, which were included in the cable network; electricity was finding its way into the remotest parts of the country. In the villages this easily applied form of energy in numerous cases gave rise to - originally small - milling industries and factories, which made the industrial windmills superfluous. Again mills were mutilated or pulled down; the area thus becoming available was used for expansion or for other purposes.
Polders which for one reason or another had not yet proceeded to install a pumping station, now at once passed from wind to electric power. This happened, for instance, with the 17-feet-deep Hazerswoude drainage project. In 1913 the board had three electric pumping stations erected, which made superfluous the seven windmills that used to pump the polder water in stages into the Westvaart and the eight windmills that pumped it into the Oostvaart. The whole complex, which up to that time had presented a grand spectacle, was thus lost for ever.
In the years after World War I the electrification of the rural districts was taken up again with great energy. In 1923 the board of the polder De Honderd Morgen of Wilde Veenen decided to proceed to electrify the drainage system, and consequently in 1924 and 1925 the seven sturdy windmills were demolished. In 1925-1926 the Eendrachtspolder near Zevenhuizen, with its eight windmills, followed suit; these are only a few instances out of many. Windmills disappeared in their dozens; very unsightly buildings took their place and much beautiful scenery was lost.
Separate mention should be made of the loss of the Schermerpolder windmills. This polder was drained by the original fifty handsome windmills, which were still in excellent condition, when in 1923 the polder board took the decision to change over to mechanical drainage methods and to demolish the mills.
This matter caused a great stir at the time, for it was regretted throughout the country that the powerful complex of fifty windmills, a monument par excellence, was to be destroyed at one blow. The Dutch Windmill Society protested loudly, numerous articles appeared in the big newspapers, reports for and against were drawn up, and although this delayed the execution of the project until 1927, the end of the affair was that the decision was carried through. At first a part of the polder was still to be drained by a number of windmills, but it was not long before these mills too stopped working, so that only here and there a few of them have been left, partly demolished and converted into cottages. Thus the whole fine complex disappeared. What a splendid monument - at the same time a valuable museum - might not have been founded in honour of the great Jan Adriaenszoon Leeghwater by leaving intact this 300-year-old drainage system with its fifty windmills; a museum which for years to come would have borne witness, for the Dutch themselves as well as for foreigners, to the glory of seventeenth-century Holland in its struggle against the water and to the means with which this struggle had been fought out!
Thus, especially since 1900, many windmills fell victim to the repeatedly changing circumstances; in the western part of the Netherlands these victims were especially drainage mills, in the eastern part industrial mills.
The catastrophic dimensions which the loss of windmills was gradually assuming in the years after World War I induced some prominent people to establish a society which might check this process to some extent. Many Dutchmen were concerned about the future of the windmills and desirous to prevent their further destruction at all costs.
Then in 1923, the society De Hollandsche Molen, Vereeniging tot Behoud van Molens in Nederland (Association for the Preservation of Windmills in the Netherlands, or Dutch Windmill Society) was established at Amsterdam.
This society united all the enthusiasts and was to develop into an important element in the efforts to preserve the windmills. A competition was held in order to arrive at improvements of the mills which might prove powerful weapons in the struggle for preservation.
The big drum was beaten, public discussions took place, even at the Royal Engineering Institute. The results of all this were hopeful indeed - they will be mentioned elsewhere - but could not prevent the number of windmills dwindling further every year.
However, the public interest had been roused, and also that of the Government, especially of the Minister. The Ministry of Education, Arts, and Sciences was alive to the value of the Dutch windmills; it took an interest in them and gave its active support.
In response to a petition of the Dutch Windmill Society the then Minister of Education, Arts, and Sciences, Dr. J. Th. de Visser, in 1924 addressed a circular letter to all the burgomasters in the Netherlands, in which the importance of the preservation of the windmills was pointed out. In this circular letter the Minister requested all those concerned to inform him in future whenever a windmill was threatened with destruction, so that the matter might be investigated. He further stated that in his opinion there were reasons why it was not always inevitable that windmills in a menaced position should grow useless.
This was not all: in 1930 the appeal to the burgomasters was repeated, and a third circular letter of similar import followed in August 1939. In 1942 an inquiry was instituted by
the Ministry, by means of which it was established that on January 1, 1943 a total of 1,467 windmills existed, all of which were in full working order, and 483 more which were in more or less derelict condition.
The extent to which the war of 1939(40) - 1945 played havoc with the windmills appears from the inventory made after the end of World War II: 1,306 mills were practically undamaged, but 473 were in partially destroyed condition. In 1960 it appeared from an inquiry instituted on behalf of the Dutch Windmill Society that the number of windmills in good condition had declined to 991, viz. 397 drainage mills and 594 industrial and corn mills.
A further decline therefore will have to be avoided at all costs. Let us hope we may be spared from further acts of war, but even then in the course of the years the number of windmills will still continue to decrease, in consequence of calamities and circumstances beyond our control.
What are the causes which, apart from those already mentioned and from the special circumstances which applied to the drainage mills, lead to the destruction of windmills?
One of the primary causes is decay resulting from prolonged idleness. Idleness implies decline; this holds good in particular for windmills. The watchful eye of the miller always keeps a working mill in good repair. If something has gone wrong, it is set right; if some component wears, it is repaired, for otherwise the mill cannot work properly. The wooden parts are tarred and painted when necessary and the whole machinery is lubricated regularly. All this is omitted when a mill is idle, even if, for the sake of keeping it in working order, it works periodically and is turned now and then, to check if everything is still alright.
A windmill will stop working when, for instance, the profits of the business are no longer sufficient, owing to the conditions of the time, sometimes combined with local conditions. In comparison with former years social conditions have altered completely: the big flour-milling industries are swallowing everything that has to be ground, the miller has to earn at least three quarters of his living by trade, wages are three to four times higher than they used to be, the miller has to employ as few hands as possible and he may save on this item by investing capital in a mechanical plant instead; this in turn causes the deterioration of the mill.
However, one is sometimes inclined to wonder whether the concentration of the milling industry, whose geographical distribution in the Netherlands unfortunately is very poor, does not in itself form an argument for the necessity of preserving the existing windmills. It might be necessary some day to call in their aid, just as it was done in World War II.
The miller's trade requires devotion. This is to be met with in those who have been brought up to the trade and in the few outsiders who feel attracted to it, but their numbers are not great. Still there are more of them than might be imagined on the face of it.
Frequently a windmill can be saved by modernization. At no excessive cost a specialized architect is able to convert the living quarters of the mill - and this applies to corn mills as well as drainage mills - into a comfortable and pleasant home, with all present-day conVeniences. This is possible without spoiling the handsome exterior.
when additional storage space for the business is required, this can be provided for in such a way that the windmill with the annexes still forms a harmonious complex. A fine example is the mill at Vragender, municipality of Winterswijk, which was built in 1959. Its outward appearance is well-preserved and yet plenty of room is available inside. The millstones are normally driven by the sails; if there is urgent work and the wind is insufficient, a built-in hammer mill with electric drive takes over the wind's task. If a miller wants to appoint his business in an up-to-date way while keeping his windmill, there is always a possibility of combining the two things.
It may also happen that a part of a town or village has to be reconstructed or altered altogether, to meet the needs of modern traffic; the authorities are then as a rule all too readily inclined to sacrifice and remove a windmill that is 'in the way'. Or a project is drawn up in which the mill is enclosed by new streets and buildings to such a degree that the 'free' wind is interfered with.
Then it is time to procure such an alteration of the projects that the new lay-out of streets is in the form of a star, so that the streets radiate towards the mill or the mill square. Not only is the 'free' wind ensured in this way, but it also makes for an attractive development, centring about the windmill, and thus a harmonious and pleasant whole is obtained.
It is obvious that specialized knowledge is required for it; this is found within the Dutch windmill Society. When it offers
advice to the municipal authorities - an advice which is given free of charge - this may mean that an attractive solution is found from the point of view of town-planning, in which the windmill has a central function as a monument.
In the past decade it has been especially due to motor-way construction, town-planning, interference with the free wind caused by tall buildings or trees, agronomic demands for the lowering of the water-table to a permanent lower level, redistribution of land undertaken by agricultural services, and many other circumstances that windmills were sacrificed.
Calamities, although fortunately sporadic, naturally cause windmills to disappear; occasionally mills are lost owing to fires started by mischieVous boys or because they are struck by lightning.
As to the latter, it is interesting to trace how atmospheric electricity played havoc with windmills through the ages.
In country districts windmills are generally the highest points for several miles around and in the towns they rise above the surrounding buildings. Like towers, church steeples, and chimneys, therefore, windmills always used to run greater risks of being struck by lightning than did normal buildings. It is not surprising that mills were frequently struck by lightning - according to present-day knowledge: quite unnecessarily so - in such a way that the resulting fire reduced them completely to ashes.
It is therefore extremely important that nowadays with every restoration provisions for mounting a reliable lightning conductor are obligatory.
It has been found that, in the period between 1887 and 1934, 422 windmills not provided with a lightning conductor were struck by lightning and that in 222 cases this started a fire. Between 1917 and 1934 thirteen mills provided with a lightning conductor were struck by lightning and in none of these thirteen cases did a fire break out.
This shows very clearly how important it is that every windmill should be equipped with an adequate lightning conductor and that the latter should be periodically inspected by an expert, say: once every three years. This entails very little expense and it will prevent a good deal of trouble and loss.
Less frequently a windmill is overrun and damaged by working faster than it can stand. If the brake is then applied suddenly, the wooden brake blocks will be set on fire owing to the sudden excessive heat, thus setting the whole mill ablaze. When a gale is coming on, this may happen if the miller has not been enough on his guard or if he has failed to recognize the signs of unfavourable weather conditions in due time and take his measures accordingly.
When for one reason or another a windmill becomes superfluous, its owner may apply to the Dutch Windmill Society, which will assist him in finding a solution for the problem concerned.
A very important factor in this connection is the arrangement which came into force on January 1, 1961, according to which a miller who keeps his mill regularly in working order may receive from the Government a contribution towards the annual expense of upkeep.
When at advanced age a miller retires from business and no successor can be found, the windmill will be stopped for an
indefinite period. This means a decline; in the course of time restoration will have to be decided upon in order to avoid complete decay. The central, provincial, and municipal authorities as well as any other bodies interested in the matter will then as a rule contribute largely towards the cost of such a restoration; thus the expense incurred by the owner is relatively small.
Frequently a windmill no longer in working order is taken over by the respective municipality. Its upkeep is then guaranteed by the municipality and the mill is preserved as a local monument. It may then be put to some use, such as a local museum or as living quarters for some one to whom the charms of a windmill outweigh the lack of the comforts to be found in modern flats. Sometimes such a mill is furnished to form a pleasant reception centre for business relations or foreign guests, who like to be entertained in an old- fashioned way.
Then it often turns out that after some time and some effort a solution is found which makes it possible to reinstate the mill in its former function.
Finally there are some drainage mills which, though no longer required for day-to-day operation, are kept in good working order by the Government Department of Waterways and Drainage or a provincial administration of waterways and drainage, under the provisions of the Act for the Protection of Waterways in Wartime. The reason is the possibility of unexpected interruption of the power supply for the electric pumping stations owing to acts of war. In such a situation the drainage mills - just like the corn mills for the supply of foodstuffs - may often bring relief, as was proved frequently during the last war. Certain windmills have been assigned for this purpose and are kept in good repair. They have the same function as the inner dykes, and they may one day have to perform a highly important task.
In the foregoing we - unfortunately - had to state that a large number of the windmills still in existence are no longer working regularly; it is not impossible that this number may increase slightly further, owing to present-day circumstances.
But on the other hand there is a growing appreciation of the part played by the windmill in its natural setting, whether rural or urban. It is nothing less than a monument, and thus every year there are some mills which solely for this reason are highly valued and are restored by the Government Service for the National Preservation of Ancient Monuments.
THE DUTCH WINDMILL SOCIETY
In various contexts the name of this society has been mentioned in the present booklet, and perhaps it is now the right moment to give an account of the activities of this society, an association for the preservation of windmills in the Netherlands.
Ever since its establishment the Society has stirred up public opinion and pointed to the great loss which the Netherlands would suffer if windmills were to disappear, and to the spiritual and material impoverishment that would result from it. The competition held in 1924, which has been referred to previously, led to several improvements in the construction of certain components of windmills.
In the numerous petitions addressed in the course of the years to ministerial and other government bodies the Society again and again has advocated the preservation of specified mill complexes and mills, with varying success. But one great permanent result was achieved: a great many eyes were opened to what is at stake. It led to a more general recognition and appreciation of the beauty of windmill scenery in the Netherlands, and this resulted in aid from the most diverse quarters. The aid was given not only in the form of sympathetic cooperation from different sides, but also in financial contributions from private persons and government agencies. Central, provincial, and municipal authorities not only support the Society as such with their contributions, but the numerous restorations of the windmills themselves would not have been possible without the considerable grants-in-aid made available for them by the authorities. The first condition is always that the owner, whether a private person or a polder, has to bear a part of the expense. The Society takes preparatory measures for such restorations, brings the interested parties together, gives its opinion, draws up estimates, supervises the work. Parties are thus sure that in each case this work is performed in an impartial and expert way, and that the money is well spent.
Soon after its establishment the Society had gained the confidence of all and this has always remained so. Millers as well as mill owners, who meet with difficulties in running a windmill or find that restoration is needed, regularly apply to the Society for advice.
Annually on the first Saturday in March the general members' meeting is held, and some hundreds of persons from different parts of the Netherlands meet to hear the report on the fortunes of the Society during the past year and to witness the presentation of the certificates. These certificates are presented to those who have done valuable work during that year in the matter of the preservation of windmills. This encouragement is considered to have great psychological importance.
Each year an excursion is made to a different part of the country on the fourth Saturday in September, in order to visit the windmills in that area and enable members to see their interior as well.
The Society carried on a campaign for the adoption of provincial by-laws, and it is now forbidden to alter or pull down a windmill except with approval of the provincial authorities. This offers an opportunity for the institution of an impartial inquiry so as to find out whether in a given case something may be done to save the mill from demolition.
The Society has addressed several petitions to the municipalities concerned, with the consequence that frequently a windmill which was on the point of disappearing was saved by being purchased by the municipality. In this way more than one hundred windmills are now owned by municipalities; thus their continued existence and proper maintenance are ensured.
Mill owners were sometimes urged to have a good lightning conductor mounted on their mill, for which they received advice free of charge. Attention is now regularly paid to this point.
Another consequence of suggestions by the Dutch Windmill Society is the institution in a number of provinces of 'Provincial Windmill Committees', which constitute important bodies, lending their aid to the struggle for the preservation of windmills. In several provinces similar work is done by directors and officials of the Provincial Administration of Waterways and Drainage. With all these committees and officials the Society regularly keeps up as close a contact as possible.
Several provinces have made an inventory of all existing windmills in their area and the results have been laid down in a provincial windmill book, which contains a great many interesting data; in turn it may form a practical basis for further activities helping to preserve the Dutch windmills.
Furthermore the Society is making efforts to establish courses for training young specialists in the millwright's profession. This is done in cooperation with the Foundation for Technical Training in the Building Trade. Without such training the millwright's craft might well die out for lack of a sufficient number of skilled young workers.
Finally - and this is not the least important point - the Society employs a technical adviser who is a specialist in the field of windmill construction and all related matters.
This adviser tours the whole country and everywhere gives advice free of charge, attends to repairs and renewals, and draws up the relative plans and estimates, briefly: he forms the central point about which are grouped all the technical activities associated with efforts at preservation and restoration.
From time to time the Dutch Windmill Society publishes its Year Books, which form the documentation of what has meanwhile been accomplished; a simple periodical, Molens (Windmills), appearing four times a year, maintains the contact with members and gives more recent news.
It hardly needs saying that a large public can be reached via the newspaper press, and this is very important in a general sense and for special cases.
And when, frequently after considerable efforts, another mill has been reinstated in its full glory, the Society will as a rule be present when it is solemnly put into operation.
Thus the Dutch Windmill Society always stands up for the preservation of windmills in the Netherlands, and it tries to attain results by many different ways and means; it forms the centre for the contact with all sympathizers, interested parties, and other bodies having something to do with the aims and objects in question, both at home and abroad.
Two organizations, the Foundation De Overijsselse Molen and the Society De Zaansche Molen, are working in the same direction locally and champion the cause of windmills in Overijssel and in the Zaan district respectively. The last mentioned society also founded the handsome and interesting windmill museum at Koog aan de Zaan. The three societies cooperate cordially. The same thing can be said of the Rijnlandse Molenstichting and similar foundations.
They aim at promoting and ensuring the preservation of windmills in their special areas. The activities of such local societies and foundations is very important; it is only by means of a plurality of organizations which are pursuing the same objects and are doing so in close cooperation with the Dutch Windmill Society that in the long run it will be possible to accomplish in the Netherlands the results which lovers of windmills would like to achieve.
The seed sown for many years past by the Dutch Windmill Society has borne fruit; apart from the more direct activity at its own bureau (where more than 200 cases concerned with windmills are handled every year), this Society has created the climate in which the idea of the preservation of windmills was able to thrive.
The Society draws its strength from the ideal character of its aims. Started with about 250 members in its first year, this number is now (1962) about 1,500. It is striking as well as typical that hardly a year goes by but the Society receives a legacy from some one who therefore during his lifetime took part in and appreciated the Society's activities.
THE BEAUTIES OF DUTCH WINDMILL SCENERY
Many paintings, photographs, and illustrations of windmills in the Netherlands show these mills in their characteristic beauty and in varying circumstances of place, season, and type. They demonstrate their great charms, to which you will no doubt be susceptible.
But you will appreciate all this much better still if you set out for yourself to visit the windmills in their natural setting, to undergo the fascination they exercise on the spectator susceptible to it. We advise you to go and see the picturesque scenery of the Dutch landscape with its meadows, its waters, its reeds, and its clouds. We are sure this picture will impress itself for ever on your mind. No doubt you will then wish to have a look at the interior of a windmill for yourself. You know the exterior, but now for the machinery with all its accessories!
Well, this is possible, and for the purpose we suggest six attractive routes, which will not only lead you through beautiful scenery, but will also afford an opportunity for entering a windmill here and there, chatting with the miller and his family, and receiving a good impression of the interior.
The scope of this book does not permit a more or less detailed description of these routes, but if you will just send a postcard to the Bureau of the Dutch Windmill Society (De Hollandsche Molen, Zeeburgerdijk 139, 1095 AA Amsterdam, Holland), you will receive a detailed printed description of the six routes, which are each of them greatly worth while, not the least from the point of view of scenery. Each description is illustrated with a small but clear route map; if you wish to look at everything in a leisurely way, you are recommended to take one day for each trip.
The six routes lead respectively to windmills in the following areas: Kinderdijk, Zaan district, the province of Groningen, the island of Tholen, the western Betuwe, and the Graafschap with the Achterhoek.
Apart from all the windmill sights, during each of these trips you will be delighted to see the characteristic features of the Dutch countryside to see its typical inhabitants, a pleasure you will seek in vain in the cities and their immediate neighbourhood.
We hope you may have a pleasant time.