"Descendants from all the builders of Babel, come to trade at Marseilles, sought the shade alike—taking refuge in any hiding-place from a sea too intensely blue to be looked at, and a sky of purple, set with one great flaming jewel of fire"
In this line you can see Marseilles as a place were people suffers. A place too hot to even stare at things as the sun reflection blinds you. The only thing that merely conforts them is seeking for shadow. By the term Babel we know that everyone is form a different place and speak different languages making comunication very difficult. It seems as a place were no one wants to be more than necessary . The sun is described as great flaming jewel of fire, meaning it is extremely hot in there. As you can realize, it is not possible to be confortable in a place like that. As you read you even fell inconfortable.
They often spoke in Free Verse
