Yesterday I spent an hour or so alone on this shore at Saltwick a couple of miles south of Whitby, North Yorkshire. Below are the remains of the harbour where 19th C luggers once beached to load alum.
Remains of the Alum works still show, but the sea eats at them. The red stain shows where the local Jurassic shale was slowly burned after which the ash was slaked with urine and the mixture reduced by heating until an egg could be floated on the surface of the brew. Alum was prized as a fixative for dye and as an agent for tanning leather. The Pope had the monopoly until some Yorkshire gentry stole away with the secret. He was annoyed and they were excommunicated.