In this passage from Book 4, Chapter 2, Eustacia and Clym have a candid conversation about the deterioration of their marriage, foreshadowing its demise. Hardy employs a metaphor of temperature change and a related idiom to convey the shifting dynamics between these characters:
‘[..] How cold you seem this afternoon! and yet I used to think there never was a warmer heart than yours.’
‘Yes, I fear we are cooling—I see it as well as you,’ she sighed mournfully.
‘And how madly we loved two months ago! You were never tired of contemplating me, nor I of contemplating you. [...]
The metaphor Hardy uses here revolves around the imagery of warmth and coolness. Eustacia remarks on Clym's apparent coldness toward her, stating, "How cold you seem this afternoon! and yet I used to think there never was a warmer heart than yours." The metaphorical use of "warm" signifies the affectionate and passionate feelings Eustacia and Clym used to share, while "cool" refers to his apparent loss of interest. This metaphor of “cooling” is doubly significant in Eustacia’s case, as she’s often aligned with burning and fire in The Return of the Native. Given this, her love “cooling” is more of a drastic change than it would be for others. Eustacia's admission of "cooling" foreshadows the fast descent that follows this encounter.
The use of the word “cooling” also has an idiomatic meaning in this passage. It situates the interaction in its 19th-century moment. In Victorian English, "cooling" was a commonly used euphemism to indicate the waning of physical desire between lovers. Eustacia and Clym's emotional intimacy has clearly diminished, but this idiom also implies that their sexual chemistry has also begun to falter and fade away.
