They discovered that they had to depressurize slowly, just like modern day divers.
America’s closest equivalent to the Brunels were the German immigrant John Roebling and his sons and grandsons. Responsible for the Brooklyn Bridge (1867), workers (and Roebling himself) were badly injured by the ‘bends’ when coming up from the pressurized footing-construction caissons extending below riverbed level. They shortly rigged up decompression chambers to combat the problem.
Yes, but this was like 30-40 years before Roebling. It was the Roebling case that made me wonder. Maybe the Thames, not being very deep, was not far enough down to create as hazardous a situation.
OK, I’ve been reading about this all afternoon, rather than working. I think the reason they didn’t experience it is that they weren’t breathing pressurized air. The caissons on the Eads and Brooklyn bridges were closed at the top and air was pumped in, which was also the mechanism by which the castings were brought out the center tube, called the “muck tube, i.e., the muck tube sucked the castings out. Apparently muck is a combination of mud and rock, which I never knew. I thought it was mud that sucked.