how is jim brought back from his visions of the past to the present ?

George interrupts him to ask for help washing up.

I was sitting on the bank, conjuring up this scene to myself, when George remarked that when I was quite rested, perhaps I would not mind helping to wash up; and, thus recalled from the days of the glorious past to the prosaic present, with all its misery and sin, I slid down into the boat and cleaned out the frying-pan with a stick of wood and a tuft of grass, polishing it up finally with George’s wet shirt.