Purveyor of Bollocks to the Crowned Heads of Europe
Thursday, 9 March 2017
A length of time
The young mason has given me the dimensions of the huge stone roundel in millimetres, not the feet and inches it would have been made in, and he has given the diamter as 915mm - supiciously close to 37 and a half inches. Hmm. I suspect laziness is involved.
The Spring and Summer ones which already exist have a foliate 'egg and dart' motif running around the edge, and the centres for these are divided into 30, not 32 as they would be if you began with a central cross and kept dividing it - 4, 8, 16, 32.
I spent quite a while yesterday in trying to calculate the circumference using Pi, but then did not trust the results. When you are dealing with a diameter which is as large as these things, a small fraction of error will lead to a gap between the 29th and 30th which is either far too small or far too big. So today I am buying the biggest protractor I can find, then mark the paper with a series of radials of 12 degrees. 360 divided by 30 = 12.
I do not believe that the original designer deliberately and pointlessly made his life difficult by using a clock-face division with these circles. They represent the Four Seasons, so they represent the passage of time, and the seasons are cyclical.
The generation after me were brought up using the post-revolutionary French system of measurement which is Metric, and do not understand why I insist on using Imperial when making or restoring things in the 19th, 18th or earlier centuries. They think I am an old man who is stuck in his ways, using pencils and paper when the computer CAD systems they have been trained in are so much cleaner, quicker and more 'convenient'. These days, they could run systems which divide by 12 or 360, but they do not - other than simple conversion tables to help them understand what I am talking about when I say 37 1/2 inches, not 915 millimetres.
You can only get into the head of a craftsman/artist who has been dead for a long time by using his methods and mindset. I once struggled to draw a large and acentrical volute (scroll) for a coat of arms which was made in 1804, and I only made the breakthrough when I realised that the varying thicknesses of line which was carved into the stone directly related to how a broad-nibbed pen works when it is being drawn for the first time. The original carver used ink pens every day of his life, whereas I had ball-points and pencils. Once understood, I had the volute drawn out in minutes.
The imperial measurements set down by the ancients could be checked at any time by using astronomy, but the ancient yard would vary in length depending where you happened to check it on the Earth's lattitude. Short measure indeed? I don't like your lattitude!
So the seafarers set up the Greenwich Observatory and made a yardstick which was as impervious to damp, heat or cold as the materials would allow, then every now and then, Customs and Excise would take their own weights and measures there to verify imports which they were suspicious about.
On the other hand, the revoltionary French baulked against the old British system and took their own measurements of one degree of longitude between Paris and somewhere else, then came up with a system which was divisable by 10, making life for the computer designers that much easier. Their seconds could well be in units of 10 too, I've never bothered to check how it relates to time.
The trouble is that they got their measurements wrong, and by quite alot.