what importance is marlow attached to? how does the narrator describe it?

Marlow is attached to the smell of oil.

We tried to get away from it at Marlow. We left the boat by the bridge, and took a walk through the town to escape it, but it followed us. The whole town was full of oil. We passed through the church-yard, and it seemed as if the people had been buried in oil. The High Street stunk of oil ; we wondered how people could live in it. And we walked miles upon miles out Birmingham way ; but it was no use, the country was steeped in oil.