The Emperor Vespasian was not enthusiastic about the development of water powered mills. He thought it would give slaves and woman more time to get into mischief.
The first flour was probably produced by a stone age woman crushing the corn seeds between two rocks. Later rocks were shaped to make the "milling" quicker, this first tool was called a quern. See the story of bread.
Remains of mills designed to be driven by water have been found in various sites of the ancient world. Norway, England, Ireland, Italy and South Africa. These mills were horizontal mills, the wheel lay flat in the river and the flow of the river turned the wheel which then turned a millstone. The millstones were housed in a mill set astride the river directly over the millwheel.
The next development was the vertical mill wheel, The wheels could be much larger and therefore produce more more power. One of the first descriptions of a vertical waterwheel was written the Roman engineer Vitruviusin in about 50 B.C. The spread of this new technology was obviously quite slow for a hundred years later the Emperor Vespasian (69-79 A.D.) expressed his disapproval of such advances:
He thought it would give slaves and women more free time and so allow them to get into mischief !
The Romans did take to the water powered mills for it is thought that it was the Romans who brought the vertical water wheel to Britain.
The picture shows two mill stones that have been dressed. The grooves in the stones channels the milled grain out from between the stones and into
This was a highly skilled job, stone dressers travelled around the country working for millers, often staying with the miller until the job was done. The stone dresser cut grooves in the face of the mill stone. These grooves allowed the flour to flow from between the mill stones, it could then be gathered and put into sacks.
The hands of an experienced stone dresser would be grey from years of using metal tools and so showing his mettle meant he knew his job. The phrase has passed into the language and now means, 'to show what you are made of'.