Dewponds and Denshers
When William Cobbett was touring upon his Rural Rides men still sought to improve their lean farms by dressing them with chalk. In some regions open chalkpits gaped in every second field; in others the chalk was laboriously brought up from dene-holes made as carefully as wells and often sunk as deeply. But should you seek to learn from books what was a dene-hole, the chances are that you will be led on a fool's dance among Danes and Druids, or at least be informed roundly and wrongly that one Diodorus Siculus, a historian of Augustus' day, put it on record that the Britons made dene-holes wherein to garner their grain; and should you consult a geologist about these extinct craters that one finds upon the Downs, 'tis odds that he will discourse to you learnedly of subterranean erosion and swallets. Yet it is little more than a century since dene-holes and marling-pits were commonplaces of daily life in the chalk-lands. John Evelyn, of salad-fame, described at length the breast-plough with which the turf was pared off at the breaking-up of a new Downland field; it came from Devonshire, and was therefore known as the Densher plough, its use as" denshering." The word was strange to the ears of the men who made the Ordnance Survey; they wrote it Densher, and you will meet it over and over again in the Sussex hills, though none remember its meaning. Truly men's memories are short; as their knowledge grows at the one end, it-decays at the other; which is after all the excuse for the existence of those queer creatures whom you call archaeologists.
Fact and Fiction
Walking over a high moor, no matter where, you may be puzzled to find that the higher you go, the wetter is the ground. It seems to be in direct defiance of the ancient doctrine that water seeks the lowest levels, yet it is a fact, and the simple explanation is that on these chill uplands the warm air from the lower levels is condensed and drops its moisture.
How else should rivers rise in the hills ? And if you watch the hill-tops from some point in the valleys you will learn that there are peaks about which there seem constantly to linger clouds, while all the sky elsewhere is clear. Those clouds are the warm currents condensing to visibility, and such points of the hills are always the wettest. Make a pond at such a point and provided it does not leak-it will contain water all the year round. Doubtless you knew all this before-in theory. The Downlanders knew it also in practice, and they made dewponds accordingly. There are places in the Downs where, on the chilliest winter's day, you may suddenly find yourself plunged into warmth; and if you look around, you are pretty sure to see a dewpond thereabouts. Some Downland shepherd had learnt the secret of the spot long years before you blundered into it, and there his dull wit found a means to circumvent the power which made the hills bone-dry.
How to Make a Dewpond
Therefore also it was needless to fence it. On the other hand you had to see that it was kept properly puddled.
A Sussex pond is almost always round and shallow.
Wiltshire ponds were of another kind. They were-and are usually square and deep, and their making was a " mystery " in the mediaeval-sense of that term, a trade secret which needed a " master " workman's help. You made your hole as before, throwing up the excavated " dirt " or "brick" in a solid vallum all round. Over the floor you laid two inches of well-puddled clay, dressing it to the smoothness of a wall; and over the clay you laid half an inch of hot quicklime with the care of a plasterer, working always from the centre so as to avoid damaging the work. Working then in the reverse direction you laid nine inches of clean straw over the whole basin, as neatly as a thatcher on a roof ; and over the straw you scattered " dirt " to the depth of a foot, finishing, if you pleased, with a thin layer of flint. Under the action of water the quicklime formed a cement, which covered the whole basin. The " dirt " and flint were to prevent its fracture by the feet of animals; and the, straw was to prevent similar damage when the " dirt " was laid on.
Such a pond was costly to make, but it needed no further attention save adequate protection from heavy animals whose feet might sink through the " dirt " and crack the thin lining of lime which was the real secret. Therefore, such a pond must be so fenced as to keep out anything bigger than a sheep.
Such was the method as described to the writer by a man who had practised it, as he stood beside the pond he had built 20 years before, a big one, in the torrid summer of 1921, and saw that even then it had abundant water. But probably the making of ponds is as the making of tribal lays, and
From Downland Pathways, 1924 pp 225-229 -
by A. Hadrian Allcroft - Published by Methuen, 1924