1. Contrasts how the speaker was before and after the revelation of nature's power, highlighting how the experience has acted as a catalyst in his development
2. When the speaker is setting out, his oar strokes "melted all into one track" showing his easy movement
3. After seeing the mountain, his rowing becomes laboured as he starts "heaving through the water", showing his loss of control
4. The initial calm and relaxed rowing is contrasted with the frantic rowing back to shore