Marking time
Question: In The Regency Underworld, by Donald Low, there is an
engraving of Brixton Prison in London, which I believe was drawn in about 1800.
On the roof is what appears to be a vertical-axis windmill. The framework is a
horizontal “H”. From the halfway mark to the outer ends of the arms are six
vertical slats on each side. How common were these mills, how did they work and
what were they used for?
The letters below suggest that the frame might have been either a
vertical-axis windmill or an “air brake” designed to increase the labour…
