Daily grind

In 1794 there was a survey of the river Don, in Sheffield, which reported that there was an average of four mills per mile. These were not just the traditional corn-grinding watermills that feature so much in 19th century buccolic art. By then, the industrial growth of the city was in full flow and the 'mills' included 'cutters' wheels' (sharpening blades), silk mills, paper mills, cotton mills, snuff mills (tobacco), and large iron-forges, all using water as an energy source. It was lack of space, as much as cost-benefit analysis, that drove the growth of coal-fired steam as an alternative source of industrial energy

Now that we are desperate for carbon-free energy, it surprises me that we have not devised or deployed modern solutions that tap the power of the rivers in the way the old mills once did - particularly in places like Sheffield, where fast-flowing water is coming from the high land on its doorstep

Grinding grain in watermills was a development from hand-grinding that had been taking place in Britain for many millennia. 6,000 years ago, a long stone, a bit like a rolling pin, was rubbed back and forth, two-handed across a flat stone with a lip at the front and the back. This was called a 'saddle-quern', 'quern' being the generic name for specialised stones used for hand grinding (and being the root of place-names like 'Whernside', where such stones were quarried) 

The next technological step did not happen until about 400BCE, when rotary stones for hand-grinding were introduced. These comprised a flat or saucer-shaped base-stone, with a similar diameter top-stone that has a vertical hole it its centre, down which grain is poured. A hole on the side of the top-stone accepts a wooden handle that is used to rotate the top-stone against the base and grind the grain. This is a lovely example of a top-stone, maybe 50cm high and 30cm across. It is called a 'beehive quern'. I can't imagine why it caught my attention

One oddity is that top-stones are much more commonly found than base stones. You can make up your own theory about why that might be so, because that's just what the archaeologists do. No-one really knows