When the snake first came to the water-trough, the narrator was excited and glad "he had come like a guest in quiet, to drink at my water trough." He "felt so honoured" at this visit whilst at the same time, the voices of his "accursed human education" advised him to kill it, for it was a gold snake and therefore venomous.
Those voices said to him, "If you were not afraid you would kill him." The narrator "picked up a clumsy log And threw it" at the snake when the snake was leaving. Like for a moment, the majestic spell of awe was broken and the voices overpowered him so his real cowardice shone through. He had asked himself whilst feeling this awe, if it were "cowardice, that I dared not kill him?" but his real cowardice came when the snake's "back was turned."
I also think that when he threw the log at the snake, it was almost a cry out that he was not to go. He said that it was his voices, but it seems to me that he used that as an excuse. That he was almost trying to punish the snake for leaving him. The narrator says he felt "A sort of horror, a sort of protest against his withdrawing into that horrid black hole" then he threw the log.
The use of words like silently, softly, in the beginning when he is first describing the snake and the snake's motions, serve to get us into a quiet, observing mood.
The narrator describes the snake and it's movements well to create the atmosphere. The use of words like silently, softly, in the beginning when he is first describing the snake and the snake's motions, serve to get us into a quiet, observing mood. Then saying the snake "mused a moment" gives us the impression that the snake is "like a king", quiet and majestic. Again, later in the poem, using words such as dreamily and slowly, projecting that quiet atmosphere.
The narrator seems almost confused by how he feels toward this snake. His voices tell him he is a coward and that he isn't a man because he hasn't killed...