Stonehenge: The Stone Mason and His Craft. (News & Notes)
Adamson, Tom, Antiquity
The words Stone Age create a seemingly unbridgeable gap between `them and us'. The following study of Stonehenge reveals a human being of ingenuity, resourcefulness and skill decreasing the gap and creating a continuing brotherhood of stone masons.
Stonehenge was built in several phases, Phase III being the structure visible today. R.J.C. Atkinson and others seem to be convinced that the structure required hundreds of men, toiling over several hundred years to completion. Demonstrations by archaeologists and engineers envisage large numbers of men, swinging on levers, resting on precarious fulcrums. This method can confidently be assumed to have resulted in many injuries, fatal and disabling; and begs the question of the willingness of the labourer to be the next victim of a toppled Sarsen upright. There is only room around the end of a lever for a limited number of men, whose weight would have been clumsily inadequate to raise the large Sarsen ring uprights (to say nothing of the Trilithons) with the stones kept continually under control. Studies have been carried out suggesting that the builders understood the intricate movements of solar objects during the earth's rotations and orbits of the sun. It is suggested this understanding would allow for an intelligence capable of seeking a solution to minimize the loss of life and limb.
It should be remembered that whether today's large crane, with fulcrum point and counterweight with jib cables, is used, or a timber lever with human counterweights, the same engineering/ mathematical principles apply. FIGURE 1 illustrates the form a Stone Age rig might reasonably assume. The rig shown is of raw timbers, being 8 to 12 inches in diameter and of varying lengths, as required. The main lever is the longest piece, around 40 feet long. Using this rig it would be possible for a handful of men to carry out all the work at Stonehenge, including the fixing of the lintels.
[FIGURE 1 OMITTED]
To replace men swinging on a lever, a counterweight basket has been used, loaded with stones of no more than 50 lb each until the counterweight totals 10 cwt. This lever is then capable of lifting 15 tons at the short end, but the vertical lift of the load is approximately only 3 inches before the counterweight touches the ground. To improve the height of the lift at each stroke of the short end, the stroke of the counterweight must be increased. This is achieved by excavating a hole directly beneath the counterweight, allowing an improvement of travel of c. 3 feet and leading to a total down-stroke of 5.6 feet. There is ample proof of these excavations in the existence of Z and Y holes. Each erect Sarsen stone has a pair of holes situated for this task and that of hoisting the lintels. The outer Y holes need to be approximately 30 to 35 feet from the stone to be hoisted. If the short end distance of the levers from the fulcrum point was 15 inches with the counterweight distance 35 feet from the fulcrum, this would give a ratio of approximately 28:1. This vantage, with the 0.5 tons of counterweight plus the weight of the lever, would lift 15 tons vertically by approximately 5.75 inches with each stroke of the lever. The counterweight could be charged and discharged by one man in around 12 minutes: thus, one man is capable of hoisting 15 tons approximately 14 inches in height in one hour. One of the Sarsen uprights could be hoisted into a vertical position in around 12 hours by one man working continuously. Allowing a reasonable amount of time for each upright, food and rest, plus a week for excavating the stone hole, moving into position the lifting rig and excavating the counterweight hole, the time taken to erect 30 uprights in the circle would be approximately 30 weeks. …