Write the central idea of the poem Fog in 60-80 words.

The movement of the fog that the poet sees over Chicago is similar to the movement of a cat. It comes and it goes surreptitiously and silently. It approaches the Chicago harbour as it is attracted to the water particles present there. But it is only a temporary visitor. It does not settle down into one place, and sits on its haunches, ready to leave at a moment’s notice. It is not there to stay, and it leaves as suddenly as it had come. The poet has seen fog before, but it has never awed him as it does now with its implication of an impending and unknown threat that cannot be clearly seen, felt, or understood.