Final answer:
The quote in question does not match any of the excerpts provided and appears to be neither a known literary quote nor a historical statement. It may be a metaphorical reflection on change, either as a natural process or a societal alteration.
Step-by-step explanation:
The quote “Ices are melting... We don’t know if it’s because spring is coming or the palace is crumbling.” does not directly correspond to any of the excerpts provided or any specific, well-known quote from literature or historical texts. The provided excerpts discuss the metaphorical and literal concept of melting ice in different contexts: Robert Frost's poem is a metaphor about human emotions using the images of fire and ice, while Louis Agassiz's work is about the physical glaciers. The poem by Du Fu reflects on the state of his country during political unrest, and Wallace Stevens' poem “The Emperor of Ice Cream” delves into themes of reality versus appearance with no direct mention of melting ice in the context of springtime or a palace. Therefore, the given quote might be interpreted metaphorically, reflecting the idea of change, whether it is due to a natural seasonal transition or a significant breakdown in societal structure.