Felt!
Funny stuff, felt. You might think of it as a material for costuming, hats, or artwork, but it played a fundamental role in the most advanced transportation of both the eighteenth and the twentieth centuries. Long time readers of this blog (both of you) may remember when we crossed the Pontcysyllte Aqueduct, perhaps the greatest engineering achievement of the canal age. It is a mighty iron trough held up on stone piers. The sections of cast iron were bolted together…