Stonehenge Solved Its Three Observatories, Who built them, How and Why

One can well imagine the returning Model team gave a good and detailed account of themselves and infecting the next one with their enthusiasm. Unfortunately, upon arrival on the site their successors mistakenly worked to the remnants of the original sarsen circle circumference of the Model team, not their revised one, Fig 41 (i). (The unlikely alternative scenario is of them driving a stake into the wrong centre hole before erecting mast 152.) The outcome was that while their construction circumference, near upright 03, was correctly positioned, completion of their part of it at stone 07 was 47cm (18in) outside of its proper position. This was to cause problems for the next team, as we shall see. There must also have been a fault with beam 106 because the fourth and last team were unable to rig the hoist-assisted spar there, see chapter 18. These were not to be their only misjudgements. It would seem that, like many conscientious students, they did what they were told but overlooked checking the validity of their conclusions. For this reason they have been afforded the tags The Learner Team, and Sector.

Their first construction task was erection of mast 152, the first stage of this being erection of an upright in position 52. The cross sections of stones 51 and 52 are seen to be disparate, Fig 42: the latter is thicker and more rotund and in these respects has more in common with the Heel Stone 96. The following scenario may account for this together with the absence of the Heel's fellow at the arch. The team became impatient about the late arrival of the intended stone 52 from the quarry and decided this justified cannibalising the arch for the fellow as a spare. This had one smooth, flat side whereas the Heel did not. In doing this carelessly, or through bad luck, the top 60 cm ( 2ft) of the Heel broke off at an angle, causing the beam to fall and lose a fractured end in turn as it fell on to the broken piece. They moved the damaged beam to one side out of the way, and one assumes they re-employed the broken pieces. The weathered remains of the damaged and leaning Heel (and the redeployed broken beam, as we will see in chapter 16), are not quite all we can see of the episode today: a waymarking ditch was dug around the Heel to prevent people walking into it.

Their erection of mast 154 was without incident, although in re-scribing its intended location they positioned it 60cm (2ft) too far southwest and at an angle of 16deg from the installation's centre line instead of 21deg. The cross section of its upright 54, contrasting as it does with its fellow 53, may indicate it was the stone for mast 152 and which, earlier, the team was too impatient to wait for. Their sector of the sarsen circle was tackled next, commencing with upright 04 and beam 103, and progressing round to upright 07 and beam 107. Not withstanding the putative fault at beam 106, the quality of their stonework, including the foundations, was to the Model team's standards but with a distinguishing feature: their uprights were worked to have tapered sides, in the classical Egyptian style as evidenced in the pylons at Luxor. This adherence to the aim-design was rarely repeated.

For an understanding of the second distinguishing feature it is necessary to explain the methods of construction. These were founded on four principles which governed all the work on this site. The movements of stones were by levers and fulcrums and they were always positive, or by compression; they were never in tension; which is to say movements were always under control. Next, the levers were of timber: any size tree stem up to 15 metres (50ft) long, or more, and 183cm (6ft) diameter at the bole. The weights of these were deployed to offset those of the stones. The largest levers could only be manipulated by lesser levers, which is to say the use of levers was often progressive. Thirdly, in contrast to the large sizes and huge weights being manipulated, movements were always small and incremental. Finally, the physical safety of workmen was paramount. In short, movements were premeditated, controlled, inching and safe. As we saw in the previous chapter, these principles were shared by the Egyptians and those who built Avebury, although in different contexts. The latter had unworked stones, but plenty of space round each stone; the Egyptians had partially worked stones but were constrained by one or two nearby stones already erected.

The stages of raising an upright to be vertical are thought to have been the same in principle as those speculated in the context of Avebury. Here, at the Stone henge there are only two firm clues. Every foundation had a 45degree ramp dug to meet its bottom. Additionally, today there seems to be no trace of the subsoil being penetrated by construction equipment (but 30cm (12in) of this has been lost in the interval through weather erosion). However there is plenty of evidence for how a beam was raised and positioned, see Figs 43/8. Of these figures, the last is of particular interest for two main reasons. Firstly, it depicts the long smoothed stones (brought from Presceli without the use of 'A' frames, as described in chapter 14), in action as pairs of legs (nos. 67and 69, X and 70) in two, so called 'pommel' and 'shackle' frames. Their ends and all the other stones in the frames, bluestones, were fashioned on arrival at the site to ensure a properly fitting assembly. This took into account the holes dug in the chalk to receive them. The second point of interest is the delicacy of the method of manipulating the complex mating process: tongue with groove, mortice with tenon, and the underside of the beam with the narrow edges of the tray in the upright's top. The effort expended in creating, setting up and using this equipment, starting with the quarrying at Presceli, demonstrates the over-riding reality of the four guiding principles for manipulating stones.

The geometry of the joint implies the use of chisels for its fashioning, but as yet none has been excavated at Stonehenge; but none has been found in Egypt either. However, they must have existed because some unsmoothed sculptures in granite at the British Museum are wholly covered in chisel marks. Tools of cold worked bronze containing obsidian (natural volcanic glass, to be found in Egypt) have been suggested (ii).

At this point the second distinguishing feature of the Learner team's work, mentioned earlier, can now be explained. When the process of raising a beam was completed, and the equipment dismantled, the tree stem lever had to be withdrawn from the gap between the uprights, rolled clockwise to be in line with the gap where the next beam was to be raised, and reinserted there, Figs 46 and 47. The new guide post holes were then dug adjacent to the points of wear marks on the stem. The circular path of the rolling stem (it was tapered), was tighter than that of the curve of the circumference of the sarsen circle, with the result that on each occasion of its rolling, its nose needed a nudge backwards to offset this. The Learner team overlooked this necessity. This, coupled with their local circumference being too far outwards, resulted in their inner guidepost hole Z7 for raising beam 107, penetrating the ramp of upright 07. However, there is no evidence of this causing trouble.

The stone guideposts would not have been sufficiently stable unless they had been in near glove-fit holes and steadied in them with timber wedges. The Y,Z holes we can discern today result from digging them out, Fig 47. What is not obvious are the methods by which a guidepost was raised to vertical, positioned over the hole and lowered into it without deleteriously scraping the sides. It is noteworthy that a narrow face of the guidepost always engaged with the treestem lever. While this served to minimise potential friction and alignment difficulties between the two, it would not have contributed to stability of the guidepost within the chalk, as would have the wider face had this been employed thus.

The precision implied by the design of the joint, the equipment employed for assembling it, and positioning of the flat, smooth face accurately on the scribed circumference, all point to the foundation of the upright being completely stable, yet its butt was asymetrical as viewed radially, and left rough hewn. Consideration of how this seemingly paradoxical result may have been achieved is of interest. During the erection process the faces and sides of the upright were to be clear of the topmost sides of the foundation hole; this ensured the hole remained clear of contamination possibly arising from the upright grazing the sides. Stability was derived solely from the butt in the bottom of the hole, which points to a perfect fit of the two. To achieve this it is envisaged the lower hole was dug to approximate to the shape of the butt, while the upright was poised at an angle when resting on the ramp, where it could be best seen close at hand and copied. With this done water was poured into the hole to saturate the chalk, Thereafter, when made vertical, the 25tonne weight of the stone (with its unfashioned top), generated plastic flow of the chalk around the rough surfaces of the butt to provide an exact fit. This stabilised after a delay during which the water was squeezed out, allowing fashioning of the top to commence. The gap between the stone and sides of the hole were finally filled with rubble, after the vertical poles acting as rubbing strips had been inserted, Fig 45.

To achieve accurate positioning of the smooth, flat face of the upright on the scribed circumference, the following procedure may have been adopted. On the upright being raised it was deliberately arranged that on reaching vertical, the face was just inside the circumference. Thereafter the stone was made to creep outwards to coincide with it, by teasing out chalk from under the outward side of the butt with the fashioned ends of staves, while the upright was supported by props. This would have been done while the foundation was still saturated. The asymmetry of the butt allowed prediction and working of the direction of the stone's sideways movements, more conveniently than had the profile been symmetrical. The ramp had two functions: allowing access for this process as well as providing ground clearance for raising the upright. Fashioning the top of the upright in preparation for assembly of the joint could not commence until the foundation had thoroughly drained and compacted sufficiently to ensure complete stability and removal of the props.

It is possible to imagine the patrons of the project being impatient for news of meaningful observations of the Moon's paths, and that the Learner team was therefore motivated to rig some stations, including a high elevation one, to take back home the first significant early results. But this is unlikely to have been the case because a particular circle bollard in their sector, no.32, did not become available until the beginning of the fourth tour. Before they left the site members of the team carved two groups of axes on upright 04, an axe on 05, and two hilted daggers and four axe heads, on mast upright 53. It would be interesting to know how the team reported their results. It is fairly certain they would have described their unfortunate experience at the arch, but they may have been blissfully unaware of their mistakes with the base circle circumference, the positioning of mast 154,and the possible problem at station 106. Nevertheless a searching listener may have deduced the reality from what was said, for example, from a chance remark about the guide post penetrating the ramp.