<< Feature Articles >> The Great Stone Circles – How they Work Part 12
Submitted by JACKME on Wednesday, 30 November 2005 Page Views: 6040
Neolithic and Bronze AgeCountry: England County: Cumbria Type: Stone CircleInternal Links:
Finding the focal point of the circle
Now comes some difficult to comprehend research resulting from over 10 years work, compressed into this short article. It may look complicated, but don’t be put off. I hope after reading this you will have an entirely new concept of what these ancient people did. The four major concepts I put forward demonstrate the extremely advanced state of their civilisation.Very early into my researches I borrowed a builders dumpy level calibrated in degrees for traverse (a survey line plotted between angular points). I set this up at Swinside where the lines for the midwinter and midsummer solstice sunrises crossed to measure the distance from that point to each stone and take its angle.
Measuring to the stones from this point soon presented difficulties because I had to decide which part of the stones to assess. I settled on measuring to the nearest part of the standing stones at ground level. These measurements showed a gradual change with no obvious jumps. I then took the bearing to each stone starting at Stone 1. After a very few readings to the estimated nearest degree, it appeared that an angle of 4 ½º touched every stone as far as I went. On rough plotting onto an enlarged photocopy of the diagram from John Waterhouse’s book, it appeared that the stones were erected opposite one another with a few blanks, and that all the connecting lines went through one point. (I now know that the same thing happens at Castlerigg and Long Meg). I then spent months trying to find how they might have constructed an angle of 4 ½º using standard right-angled triangles, as suggested by Professor Thom.
Realisation eventually dawned, that perhaps there had been a fault in the level I had borrowed and that it was out. Perhaps I was looking for the wrong angle, but it must be something close to it, as the ancients appeared to have built at regular angles. What could it be?
I then thought about what instruments they probably had - various poles, and some cord with which to make a simple compass. At school I had learnt how to divide lines and angles with a compass. I then realised that if I drew a circle with the compass, then divided the circle with a line through the centre, and continued to divide the line by compass to give a 90º right angle and so on, I came up with this:
1. The dividing of the stone circle into equal angles.
The circle is drawn with a compass of some type.
1.The circle is divided by a straight line through the centre to create and angle of 180º.
2.This line is divided into 2 equal parts by use of the compass to create and angle of 90º.
3. The four quarters were divided again by compass to create and angle of 45º.
4. The eight 45º angles are divided by 2 to create 16 angles of 22 1/2º or 22º 30’
5. The 16 x 22 1/2º angles are divided by 2 to create 32 angles of 11¼º or 11º 15’
6. The 32 x 11 ½º angles are divided by 2 to create 64 angles of 5 5/8ºor 5º 37.5’
7. The 64 x 5 5/8º angles are divided by 2 to create 128 angles of 2 13/16ºor 2º 48.75’
8. The 128 x 2 13/16_ angles divided by 2 to create 256 angles of 1 13/32º or 1º 24.38
9. The 256 x 1 29/32_ angles divided by 2 to create 512 angles of 45/64º or 0º 42.19’
10.???
This divides the circle into 512 Divisions with the instruments that they had available. They could have gone to the 10th division, but no proof has yet been found. They did not use our 360º circle
Many readings show the common use of the angle of 5º 37’ ignoring the decimal factions of the minute, as it is unreal to read the stones to such a figure.
The most intriguing question is how the ancients laid out the circle. Could they have used a cord compass every time? This would have been very time consuming and likely to create inaccuracies which are not apparent on site. Or perhaps they had some other instrument?? Has anybody seen such an instrument?
2. Thom noted that there are several pairs of stones aligning to the solstice sunrises and sunsets. When all these parallel pairs are drawn on to a single diagram as here, we see that one pair for each group cross at one place. I call this the Focal Point of the circle. Please note this is not the mathematical centre - the North/South line does not quite go through this point.
3. Having found the Focal Point of the circle at Swinside, I set up the theodolite at that point. Only reading to those stones that are still in their original positions, I confirmed the 5º 37’unit, or a division of it, as the spacing of the stones, where one was required. It has been noticed that the observation of the First and Last Gleams at the solstices were often past the edge of the fore sight stone, suggesting that it would only have been visible on the actual day. Unfortunately we can never see this to prove it.
4. This exercise confirmed that the North/South line did not go through the Focal Point, but went very near to it. There had to be a reason for this. The idea was formed that they must have stuck in a post as a construction sighting marker. Several sizes of pipes up to 20 cms, were tried to test this theory, but none worked exactly. On deeper thought it was realised that they did not have straight plastic pipes available or indeed wooden poles of a uniform thickness, so they perhaps used a tapered tree instead. Hence the pyramid of plastic pipes in This photowhich is the reverse of the midsummer sunrise seen by the edge of Stone 46 at Swinside to the rough chipped notch in Stone 16. The wind has caught the plastic pipe pyramid, the other side of the pipe aligned exactly before the wind blew. This was taken with the old film camera so was not seen until the photos came back.
This suggests that the ancients lined everything up by the edges of the tree, hence the reason for the North/South line being slightly off the Focal Point. It was calculated that in this case the tree had to be about 4 metres high, so that the last gleam of the midsummer setting sun over the very high skyline, with an elevation of 14º 50’, could be lined down to the stones accurately. They got the layout calculation slightly wrong and so they had to hack a rough notch out of Stone 16. This photo shows the line between Double 42/43 and 13/14.
This photo shows the North/South line through Stone 29 at Swinside, the Southern stone, with a rubbed notch on the other side, through the left hand side of the base of the plastic pyramid to the little North Stone 57, which has been rolled over, but is still more or less in the right place. The top of the pipe points roughly to where the fallen standing stone marking north lies on the next hillside.
The same thing appears to have happened at Stonehenge where the lines for some of the moon observations go around a posthole, (No 3362). This is said to have been 18” in diameter, according to the tables in ‘ STONEHENGE in its landscape’. It appears that this happens at several of the other postholes, including those well noted by the Heel Stone.
The sizes of the trees used depended on the height of the expected observation to be required. Once the circle was constructed the tree(s) were removed. There is excavation evidence that this happen at Moor Divock in Cumbria and there is a strong suspicion that the same system was used at Woodhenge in Wiltshire. There are however, two problems with the Woodhenge site. Firstly, there is the question as to whether the concrete markers were placed absolutely accurately. Secondly the trees around Lark Hill have spoilt the final MSSS observations, but the earlier evening ones indicate that the system was there. Much more work needs doing here.
If you find all this impossible to believe, go and try it for yourself, and then tell me where I am wrong.
Next: The Orientation of Stonehenge
Contents page for the whole series is here
Note: This is the sixteenth of a series of previously unpublished articles by retired farmer, Jack Morris-Eyton. This week Jack reveals some of his fascinating experimental archaeology.
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