It woyld be funny to me if it turned out the secret was urine instead of seawater. One of the bits of received wisdom i got from my grandfather was peeing on your hands toughened them up. He claimed it as a bit of advice he was given on his first day chopping hardwood for a steam engine at a tin mine. I figured it as a first day prank like being sent to find headlight fluid in modern times but he said it was true.
Before major industrialisation, people used what was at hand. I think the peeing on your hands thing has been long debunked but in roman concrete it may have worked.
Before major industrialisation, people used what was at hand. I think the peeing on your hands thing has been long debunked but in roman concrete it may have worked.