Denny:
I guess most would call it a sediment trap. It’s that little filter sort of a thing with a clear glass bowl placed somewhere along the fuel line . On our old cars my dad would point it out to me. Then he would show me that there always seemed to be a small amount of rusty water in the bottom of the glass bowl.
I guess in the “old days” one could never really trust the gas station to not have a little water in their tanks. Also there was the constant breathing of the gas tank itself as the cool nights and warm days changed the air pressure in those old atmospherically vented tanks