Answer:
It establishes an earlier time period.
Step-by-step explanation:
The use of the phrase "I know not" instead of "I don't know" emphasizes the fact that the story is set in a past period of history, and not in modern times. This is clarified in various ways in the excerpt. The author also uses phrases such as "the shades of evening," which give the setting a feeling of the past, as well as an indication of the speaker's character and education.