August 20, 2019
There are any number of Universals in the Art of Design. The Golden Ratio of 1.61 through which your belly button divides your body or the sides of a piece of paper. Logarithmic spirals generated by exponential growth, ie: Life. The 120 degree angle and it's complement of 60 degrees. All of these are ratios found throughout nature, and our neuro-systems are optimized to find within them a quality that we call beauty!
There are other fun factors that a designer keeps in mind about how we perceive visually. Our eyes track and accentuate light/white, and less saturated colors. And important to the fine art of shaping and placing stones, we emphasize the visual weight of concave silhouettes, and de-emphasis the convex. Consider the Great North Stone.
Here the surveyor's rod is placed in line with the "Visual Center of Gravity," the center-line of the visual mass of the stone's outline as we perceive it.
However the actual physical axis of rotation would be about 8 inches to the left ! As you can see there is considerably more rock to the left of the rod than to the right. In setting and aligning shapes, and stones, both of these factors must be kept in mind. If the stone is somewhat symmetrical the considerations can be minor. But with "ob-gnobular" stones, lopsided, heavy on one side and light on the other... judging the placement and final visual effect can be a fine art.
Pictured is one of the four stones we will be working with this year, flanking the Great North Stone. In this case the axis of rotation and the visual axis actually line up well, even though we have a non-symmetrical base. Making accurately scaled drawings of the stone to be placed, and it's relationship to already placed stones, is the key here.
Now we start to bring all of this together for the matter at hand... Building the North Copse. First we need a scaled drawing of the North Copse, especially locating the placement and diameter of the trees in the area. A bit of work with a tape measure on site, and some trig on the computer, and we get this bowl of spaghetti!
Removing the clutter we can begin trying out different alignments of the ellipse. We have to keep in mind how the small ellipse will interact with the Main Circle. And we want to avoid getting too close to tree roots, if at all possible. In past years we have been forced to fell trees that we simply could not work around. We have had trees die a few years after we gave them a generous clearance... and we have had trees live when we were forced to cut very close to their roots.
In 1994 the Stone Circle was laid out in such a way that the minor North/South axis would pass through the Hemlock tree in the North, the Main Altar and the South Gate stones. 26 years later we have come to the crux of the matter.
This drawing is the final result, and with it we can permanently stake, and the plot, the close positions of the stones comprising the North Copse over the years to come. All we need is a straight line drawn from the Great North stone to the Hemlock tree.
Ellipses have some very interesting physical properties. If we think of an ellipse as mirrored on it's inside, then any light sourced from any point within the ellipse will pass through a line segment located along it's Major Axis. The end points of this line segment are known as the "Foci." If you know the foci, and the length of the major or minor axis, you can easily calculate every other part of the ellipse! Using just a piece of string.
Stranger still, if you stood at one Foci with a flash light, any direction you point the light will collect all of the beams through the other foci. This works for sound too.
Did you know that there are two "Whispering Points" within the Stone Circle? Two people standing at the foci with their backs turned to each other can converse... in a whisper !
( HINT: Take the square root of { (Major Axis /2) squared minus the (Minor Axis /2) squared } and subtract it from the end point of Major Axis = the Whispering Point! )