Answer:
The use of capital letters in the excerpt from Emily Dickinson's poem "This World is not Conclusion" serves to emphasize specific words and concepts, contributing to the poem's overall meaning. In this case:
**"Sagacity" is capitalized to emphasize its importance and draw attention to its significance in the context of the poem.**
"Sagacity" is defined as the quality of being perceptive, and by capitalizing it, Dickinson underscores the idea that perceptive insight or wisdom is crucial when confronting the enigmatic aspects of existence presented in the poem. The capitalization adds a layer of emphasis, guiding the reader to focus on the importance of sagacity in navigating the mysteries alluded to in the verses.