Theories about Stonehenge
From The Art and Popular Culture Encyclopedia
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Stonehenge has been the subject of many theories about its origin, ranging from the academic worlds of archaeology to explanations from mythology and the paranormal.
Construction techniques and design
A recently published analysis draws attention to the fact that the stones display mirrored symmetry and that the only undisputed alignment to be found is that of the solstices, which can be regarded as the axis of that symmetry. This interpretation sees the monument as having been designed off-site, largely prefabricated and set out to conform to survey markers set out to an exact geometric plan.
The idea of ‘precision’ (below) demands that exact points of reference were used, both between the structural elements and in relation to the axis (i.e. that of the solstices). Johnson's theory asserts that prehistoric survey markers could not have been placed within the footprint of the stones, but must have been (as in any construction) external to the stones. That almost all the stones have one ‘better’ i.e. flatter face, and that face is almost invariably inwards, suggests that the construction was set out so that the prehistoric builders could use the center point of the inner faces as reference. This is very significant in respect of the Great Trilithon; the surviving upright has its flatter face outwards (see image on right), towards the midwinter sunset, and was raised from the inside. The remainder of the trilithon array (and almost all of the stones of the Sarsen Circle) had construction ramps which sloped inwards, and were therefore set up from the outside. Placing the centre face of the stones (regardless of their thickness) against markers would mean that the ‘gaps’ between the stones were simply consequential. The study of the geometric layout of the monument shows that such methods were used and that there is a clear argument for regarding other outlying elements as part of a geometric scheme (e.g. the ‘Station Stones’ and the stoneholes 92 and 94 which mark two opposing facets of an octagon). A geometric design is scalable from concept to construction, removing much of the need for measurements to be made at all.
Much speculation has surrounded the engineering feats required to build Stonehenge. Assuming the bluestones were brought from Wales by hand, and not transported by glaciers as Aubrey Burl has claimed, various methods of moving them relying only on timber and rope have been suggested. In a 2001 exercise in experimental archaeology, an attempt was made to transport a large stone along a land and sea route from Wales to Stonehenge. Volunteers pulled it for some miles (with great difficulty) on a wooden sledge over land, using modern roads and low-friction netting to assist sliding, but it became clear that it would have been incredibly difficult for even the most organized of tribal groups to have pulled large numbers of stones across the densely wooded, rough and boggy terrain of West Wales.
In 2010, Nova's "Secrets of Stonehenge" broadcast an effective technique for moving the stones over short distances using ball bearings in a wooden track as originally envisioned by Andrew Young, a graduate student of Bruce Bradley—director of experimental archaeology at the University of Exeter.
- Experts hit on the new idea after examining mysterious stone balls found near Stonehenge-like monuments in Aberdeenshire, Scotland. About the size of a cricket ball, they are precisely fashioned to be within a millimetre of the same size. This suggests they were meant to be used together in some way rather than individually.
In 1997 Julian Richards teamed up with Mark Witby and Roger Hopkins to conduct several experiments to replicate the construction at Stonehenge for Nova's "Secrets of Lost Empires" mini series. They arranged for a gang of 130 people to attempt to tow a 40-ton concrete replica on a sledge which was placed on wooden tracks. They used grease to make it easier to tow up a slight incline and still they were unable to budge it. They gathered additional men and had some of them use levers to try to pry the megalith while others towed it at the same time. When they all worked together at the same time they were able to move it forward. They were uncertain whether this would be the way they would have transported the largest stones 25 miles. To do this would require an enormous amount of track and a lot of coordination for a large number of people. In some cases this would involve towing the stones over rougher terrain. They also conducted an experiment to erect 2 forty ton replicas and put a 9-ton lintel on top. After a lot of experimenting they were able to erect 2 megaliths using a large number of people towing and using levers. They also managed to tow the lintel up a steel ramp. They were unable to determine this was the final answer but they demonstrated that this was a possible method. At times they were forced to use modern technology for safety reasons.
Josh Bernstein and Julian Richards organized an experiment to pull a 2-ton stone on wooden tracks with a group of about 16 men. They placed the stone on a wooden sledge then placed the sledge on a wooden track. They pulled this with two gangs of about eight men. To move the stones as many miles across Southern England, the creators of Stonehenge would have had to build a lot of track, or move and rebuild track in pieces, as the stones were taken to their final destination.
A recent article has argued that the massive stones could be moved by submerging them in water and towing them below an ancient vessel or group of vessels. This technique would have two significant advantages. It would reduce the load borne by the vessel while part of the stone's weight is displaced by the water. Secondly, the arrangement of the load below the vessel would be much more stable and reduce the risk of catastrophic failure. Naturally, this would apply only for transportation over water. The technique was tried during the Millennium Stone Project 2000, with a single bluestone slung beneath two large curraghs. The sling frayed away, and the stone plunged to the bed of Milford Haven.
It has been suggested that timber A-frames were erected to raise the stones, and that teams of people then hauled them upright using ropes. The topmost stones may have been raised up incrementally on timber platforms and slid into place or pushed up ramps. The carpentry-type joints used on the stones imply a people well skilled in woodworking and they could easily have had the knowledge to erect the monument using such methods. In 2003 retired construction worker Wally Wallington demonstrated ingenious techniques based on fundamental principles of levers, fulcrums and counterweights to show that a single man can rotate, walk, lift and tip a ten-ton cast-concrete monolith into an upright position. He is progressing with his plan to construct a simulated Stonehenge with eight uprights and two lintels.
Alexander Thom was of the opinion that the site was laid out with the necessary precision using his megalithic yard.
The engraved weapons on the sarsens are unique in megalithic art in the British Isles, where more abstract designs were invariably favoured. Similarly, the horseshoe arrangements of stones are unusual in a culture that otherwise arranged stones in circles. The axe motif is, however, common to the peoples of Brittany at the time, and it has been suggested at least two stages of Stonehenge were built under continental influence. This would go some way towards explaining the monument's atypical design, but overall, Stonehenge is still inexplicably unusual in the context of any prehistoric European culture.
Estimates of the manpower needed to build Stonehenge put the total effort involved at millions of hours of work. Stonehenge 1 probably needed around 11,000 man-hours (or 460 man-days) of work, Stonehenge 2 around 360,000 (15,000 man-days or 41 years). The various parts of Stonehenge 3 may have involved up to 1.75 million hours (73,000 days or 200 years) of work. The working of the stones is estimated to have required around 20 million hours (830,000 days or 2,300 years) of work using the primitive tools available at the time. Certainly, the will to produce such a site must have been strong, and an advanced social organization would have been necessary to build and maintain it. However, Wally Wallington's work suggests that Stonehenge's construction may have required fewer man-hours than previously estimated.
Note that the estimate of 20 million man-hours means that 10,000 men working on the site for 20 days each year, for 8 hours per day, could have completed it in 12.5 years.
Some commentators have suggested that the stones may have been the core supporting framework for a larger wooden building with a roof.
See also
