Hello, teachers.
I am completely at a loss how to understand the following paragaraph (from "The Nebuly Coat" Project Gutenberg text)

...the little group moved up the nave, enveloped in an atmosphere of its own, of which wet overcoats and umbrellas were resolvable constituents. The air in the church was raw and cold, and a smell of sodden matting drew Westray’s attention to the fact that the roofs were not water-tight, and that there were pools of rain-water on the floor in many places.

What I don't understand is "of which wet overcoats and umbrellas were resolvable constituents" part. They are walking inside the cathedral, and I understand the nave is enveloped in an atomosphere of its own surrounded by huge Roman pillars and vaulting. But why is it that wet overcoats and umbrellas are the elements of the specific forms being defined? Prior to this passage, the novel says "The heavy sheets of rain in the air, the misty water-dust raised by the drops as they struck the roofs, and the vapour steaming from the earth, drew over everything a veil invisible yet visible, which softened outlines like the gauze curtain in a theatre." I imagine the inside of the minster might be beclouded by mist, too, and everything might look blurred, but why are overcoats and umbrellas exceptions? Or does my interpretation totally miss the point? I appreciate any suggestions. Thank you!!