The characters are ascending a hill made of hardened mud where the castle is situated. As they move away from the shelter of the dunes, they notice fewer flies, yet the heat becomes increasingly oppressive. Stephen points out a change in color in his companion, suggesting that he should remove his heavy coat and loosen his neckcloth. This advice reflects the concern for health, particularly for those who are heavy and more susceptible to heat-related ailments.

The comment about "frank, straightforward apoplexy" or "acerebral congestion" underscores the dangers posed by the heat, especially for individuals who are corpulent. This dialogue enriches the narrative by highlighting the physical struggles and the dynamics between the characters, as well as the harsh environmental conditions they face while attempting to navigate the landscape.