Friday 16 October 2009

Sundial

Several computers later I finally manage to get onto blogger!!! We have been away as usual to here there and everywhere (well Mid Wales, Buckinghamshire, London and Northern France if we're being exact) and when I got home I couldn't get my computer to switch on. It would go to a screen which said " you did not close down properly ........do you want to open in this that or the other mode, a load more waffle and a count down timer clock. When the clock got to zero a dotty bar came across and the computer would start the whole process again. I'm sure it would still be doing it, but my son in law said buy a gizmo to put the hard drive in and connect it to another computer. £40 poorer I connected to my fathers computer - which didn't want to play either!!! I wish I wasn't such a technophobe, but I don't actually know where to get help that works for me!!!! If I read the help files they are talking gobbledygook and if I go on a course it's toooooooo basic.

Anyway enough of my whinge, I haven't done any dyeing - for obvious reasons, although I have done a workshop in Buckinghamshire which was really excellent and hopefully there are a new wave of enthusiastic dyers in that Guild! Tomorrow I am off to Gloucester to do a talk to another Guild and then on Tuesday I go to Poland for the 28th Dyes in History and Archaeology Conference, so I guess I won't get much opportunity to write other than this evening!

Yesterday was the birthday of both my John and Helen Melvin's John if you've read earlier posts there is a note from Helen asking for a sundial to be made for her John's birthday present - it was duly delivered!

It is a polar dial rather that the usual vertical or horizontal dials that are most commonly seen on walls or in gardens. They have to be made specifically for their location or they won't tell the time accurately, but this dial is the same wherever it is - however your latitude and longitude are very important - it has to be positioned at an angle equal to the latutude of the location and facing south.

It is made from Welsh slate from the Berwyn Slate Mine in Llangollen and hand made, polished and carved with all the details needed to tell the time. I have to confess that I am beginning to appreciate more and more the many complex ways they had for telling the time in the past. Before the advent of the trains we had different times in different parts of the country (UK I'm talking about here, but I think it must have applied everywhere) it was only because you needed to know what time a train was going to arrive or depart that it got changed!

The gnomon and pillars are made from brass, the box on the left hand side is the equation of time - this indicates the difference between clock and sun time. The earths orbit round the sun is an elipse, not a circle so there are inequalities between the two times, you have to add or subtract the difference shown on the chart from the dial to get the "clock" time. Easy!

Then you need the sun to shine!