Tuesday, 7 August 2012

The date stone debate

Of all the questions raised by the investigations into 34 Mill Street, the nature of the date stone is one of the most fascinating. For starters, the actual date of the stone was never covered, and the removal of the render simply exposed the full size of the stone so like many townsfolk I've been walking past this for 30 years without noticing. There is also plenty of debate as to whether there are even date marks on the stone or whether people were projecting their own interpretations onto the marks, or whether the marks might be mason's marks and natural indentations. Further doubt as to the stone's authenticity rest on the fact most date stones of this period are inscribed with roman numerals as opposed to the arabic numerals we see on this example.

The date stone in situ in the wall of 34 Mill Street.

Personally, I've always thought the stone has a date on it. I've spoken to so many people that agree (including those who have wandered up to see what I was doing), and one gent who knew of the stone 70 years ago; more on that story later. So there is a consensus the stone shows a date (those with opposing views are invited to state their case in the comments section). However,  a consensus proves nothing so I decided to see if we could find firm evidence that the markings on the stone were a date.

A dinosaur footprint captured by photogrammetry. This is an untextured 3D model.

This is the original footprint, a Eubrontes from the Warner Valley, Utah.
As you might guess, this is way older than our date stone (and possibly better preserved).

How to accomplish this? Well, I've recently become a volunteer research associate with the University of Southampton where I am at present working on techniques that allow the study and interpretation of dinosaur footprints and other trace fossils. One of the methods we use is photogrammetry, a process which entails the taking of overlapping photos which are then analysed by software that generates 3D data, and from that we make accurate models of our subjects which we then use to check the morphology of the print on the computer. I used the same techniques to have a look at our date stone, and here are the results.

The textured 3D model (or mesh). This is generated from several overlapping photographs.

The mesh with the texture removed and a simple 3-point light rig. Without the visual clutter
of the texture we can now see the surface of the stone clearly.

Now the same mesh with low-angle lighting. This is adjustable and allows us to
see we could not see under normal conditions as we can light the stone from any angle.
See the movie below.

The movie above shows a light rotating 360 around the mesh, which enables us to see the details otherwise obscured by shadow. Try stopping the movie and scrubbing along the timeline to take a good look at the stone under the different lighting angles.

False-colour image of the mesh based on elevation. Red = Low, blue =  high.
This clearly shows the numerals on the stone.

The images generated during this analysis show numerals carved into the stone and not mason's marks or natural features created by the bedding plane of the rock or weathering processes. I would suggest that the date says 1400, but the weathering the rock has undergone over the years has damages the surface and the third digit is obscure.

So is the stone authentic? We know the stone has been there since 1915 as John Earle's mentions it in his book The Streets and Houses of Old Macclesfield, and he states the stone says 1400, and this is the earliest mention of it I have found so far. The stone does not appear to have been forgotten between then and now either, and as I mentioned earlier whilst at the site I was approached by an elderly gent who told me that after the second world war he worked as a painter and decorator and was involved in painting the outside of the shop. He said the then owner asked the workers to scratch a little at the numerals to ensure they didn't disappear, which they did using a nail. He emphasised they didn't chisel at the stone, just scratch it. So we now know the stone has been 'retouched' at least once since 1915.

Andrew Ramshall has sent information regarding the stone to English Heritage and we await the results with interest. If the stone was verified as being medieval then it would be of potentially national importance as it would represent a very early example of arabic numerals used in a date stone, plus it might well have a connection with the castle. However, it might be there is no way the stone can be dated with any accuracy and the fact the carving has been touched up might have a bearing (or it might not).

We may never know the stone's true provenance, but it is at the very least a talking point that gets people thinking about the town's pre-industrial heritage, and it's worth preserving for that reason alone.

1 comment:

  1. A fascinating analysis, with the aid of modern technology. I suppose that to some extent, the nail-scratching would emphasise what the "scratcher" thought he saw there, so there could have been an unintentional element of interpretation in that. Look forward to any further information, and English Heritage's input.