Awkward Earth Talk on Sat 12 August

On Saturday 12th August Gerry Calderbank will be giving a talk at Bewdley Museum. He’ll talk about how the surveyor’s levelling practice and technology has developed from Ancient Rome to the present day – thereby giving rise to the metric system en route.


We asked Gerry to say a little more about it.

“In the 1960s Herefordshire had no ‘County Archaeologists’ nor support structure; instead, there was reliance upon various local museum, university and/or WEA staff et al. for dealing with the rescue digs – people like the late Frank Noble and Stan Stanford for example. So digs tended to be in their own spare time (weekends and vacations) and relied upon lots of volunteers such as ourselves in he W.A.R.S.  – plus the Archenfield Archaeology Group, of course.


Consequently, there was never much time for anything much more than the digging and tidying up afterwards. I mostly assisted Stan Stanford – on mainly Iron Age and Romano-British sites (the various hillforts such as Croft and Midsummer Hill, or our three Leintwardine rescue digs spring to mind) plus a couple of Neolithic sites and the Bronze Age urnfield at Bromfield, etc., etc.


Stan was always pushed for time and, instead of booking his levels in a conventional way (Surveyor’s Notebook) Stan scribbled all the data on his field sheets as we worked (Sopwith staff foresight & backsight readings) and these were left for conversion during the long winter evenings.  He lived in Luston and I used to drive over on such evenings from Burford (Salop!) to help Stan and Yvonne with the conversions and any other jobs like like washing finds, etc. 


One such evening we took a break from the tedium and Stan remarked that there must be some more efficient way of doing things.  This set me thinking.  It was a pre-digital era of course – not even pocket calculators! – but I was familiar with certain engineering techniques and (from my work) with so-called ‘Modern Mathematics’ and I realised that the simple arithmetic we were doing (subtracting staff readings from the backsight data) was actually an “iterative process” in mathematical terms – and could therefore probably be mechanised in some way.


So, to cut a long story short, I invented and built a simple form of circular slide-rule (an analogue computer) which we then used on-site when levelling. It was  calibrated in Imperial measure and, when set up (“zeroed”), you could subtract the foresight readings instantly to the nearest tenth of a foot ASL (our normal Imperial usage). 


I always assumed that Stan would have ceased to use our  ‘Woolhope Scale’ when British archaeology metricated but, just a few years ago before his final illness, three of us were visiting the Stanfords (in Leinthall Earls) when Stan went upstairs and returned with the computer, asserting that he had no further use for it and insisted upon returning it to me . . . and I then saw that Stan had ‘metricated’ it sometime – by overwriting my lettering and numerals!”

You can book your place by calling 0845 6077819